[Updated to: VERSION 1.11] One race that I have loved playing is the Xeloxi - after all, who wouldn't want to be a crime lord?  Unfortunately, the Xeloxi are considered to be kind of bad. A recent civ tier list from last month by slarjy in these forums (which is quite good btw, and incorporates community feedback) puts them dead last in F tier, and this is hard to argue with.  The AI is notoriously bad as Xeloxi, and their crime "bonus" helps to sabotage their own economy.  I am not here to argue that they aren't underpowered - better players than me can decide that.  However, I do indeed feel that many people play them improperly, and do not understand some of the interactions that Xeloxi have, specifically with crime.  I wanted to write a brief overview of how Xeloxi interact with crime, and how most players don't play them properly.  Perhaps after understanding this, players can develop strategies to give Xeloxi a fighting chance against the other civs!

I want to go over some main points with the Xeloxi that I have discerned through my experience, and why people misunderstand how they work (I will be using unaltered Xeloxi with all of their default abilities, ideologies, and traits):

1. Crime is bad - yes, even for the Xeloxi.  They do not WANT a high crime rate.  They are, however, less negatively affected by crime than other factions (which is good, because they inherently have more crime than other factions).

First, a look at how crime works, and how the Xeloxi interact with it uniquely. Crime has the following downsides to a core world's system (I use the term "system" to describe a core world and its feeder colonies):

1. Planetary income is reduced

2. Decay rate from the colonies is increased

3. Morale of the colonists is lowered

4. Increases the chance that new citizens will be "criminals", thus adding more crime once they arrive

The Xeloxi are immune to penalties 3 and 4, but they are STILL NEGATIVELY IMPACTED by penalties 1 and 2.  Xeloxi are essentially "stuck" with a higher crime rate due to the fact that their citizens are all criminals.  Because of this, they are pseudo-immune to penalty 4 (since their citizens are criminals anyway, thus unaffected by this consequence).  They are also designed to be immune to crime morale penalties (as are all criminals) making them unaffected by penalty 3.

However, they still suffer penalties 1 and 2.  For this reason, Xeloxi actually do not WANT a high crime rate.   Just like any other civ, they want lower crime.  It can be okay for them: If a world does NOT have relevant income, and does NOT have (many or any) feeder colonies, then consequences 1 and 2 don't really apply, so Xeloxi can elevate crime with no penalties (where other civs would suffer moral and crime spread problems).  However, worlds with high income (such as Savvot, the Xeloxi homeworld) or worlds that may suffer from the increased decay rate still want low crime.

A major mistake people make when playing Xeloxi is that they read the part where "Xeloxi use high crime to their advantage" and they think "oh, i must want tons of crime with this civ!".  This is not the case.  Xeloxi still want low crime, they are just less adversely affected by high crime than other civs.  Non-income worlds for Xeloxi don't mind crime increases all that much, and non-income worlds with low colony counts (thus avoiding multiple decay increases) are largely immune to crime penalties altogether.  Income worlds, such as the Xeloxi home world, still want as low crime as possible to reap as much income as possible.

Remember crime spreads from colonies.  So in general, a single core world with MANY colonies will have much higher crime than a core world with few colonies.  In fact, having lots of colonies is the main way Xeloxi worlds seem to get to excessive crime levels.  Adding a governor to create another core world, thus splitting existing colony contributions, will lower crime for each core world.

With the above information, it should be clear that missions and events that raise crime are STILL BAD for Xeloxi.  But the Xeloxi can tolerate crime increases better than most civs due to their partial immunity to the consequences, so these options aren't quite as bad for Xeloxi as they are for everyone else.

As I mentioned several times, the Xeloxi homeworld of Savvot is predisposed to be an income-based world, meaning you want LOW crime for your homeworld.  Use surveillance center, monitoring station on your colonies, etc (just like any other civs would) to lower crime on Savvot and get as much of that high starting income as possible.

2. The "crime-exclusive" colony buildings are NOT something you should intentionally raise crime to obtain.  They help offset the unfortunate side effect of high crime, which as Xeloxi, you will experience.  They are one per player (not one per colony), and there are only 3.

Another mistake people make is thinking they should get high crime, so they can unlock the crime bonus buildings.  This is again not the case, since as per my first point, Xeloxi want low crime just like everyone else.  However, it will be inevitable that some of your core worlds, especially ones with many colonies, will get high crime rates because Xeloxi citizens are all criminals.  Once your rate is high enough, that colony can make one of these buildings.  Here is a quick list (they all need 1 durantium to build):

1. Smuggler's port

     -requires 30% crime on a world to build, gives +30% wealth, no research required

2. Pleasure dome

     -requires 50% crime on a world to build, gives +10% approval, +20% tourism, requires Xeno Entertainment research

3. Mercenary camp

     -requires 70% crime on a world to build, gives +30% resistance and leader upon completion, requires Cultural Assimilation research

Notice that the highest threshold here is 70% - this should indicate that there really is no desirable reason to have crime intentionally go higher than that. In general, you want your worlds much lower than that.  That is why these are one per player, and not repeatable for multiple high-crime colonies.  It should be RARE that a world is forced to a crime rate this high, thus giving you the (perhaps only) opportunity to build one of these structures, and is NOT something that you aim for per world.  It is more like compensation if a world unfortunately gets high enough to qualify.  As mentioned above, core worlds with low income values are good targets for these, since they can maintain a very high crime rate while effectively being immune to all consequences besides very slight decay increases.

Smuggler's port helps with a big boost to income (which is offset by crime, so it seems counterintuitive - more info in section 6 on a good use for this).  You pretty much want to get this every game on your first income planet, as it is quite good.  Pleasure dome gives quite a big boost to approval, as well as considerable tourism (which again can help offset crime income penalties).  The merc camp is mainly for the leader, as there is already a 30% resistance building that you can make if that was your main goal. 

Once these building are in the queue for a core world, you can reduce the crime back below the threshold.  These buildings will still remain in the queue and can be completed.  A valid strategy is to build these on a world that happened to exceed the threshold, and then immediately try to reduce that world back down to a manageable level. The merc camp, worth noting, gives +2 military adjacency bonus.  This means you can place it, then put a Surveillance Center next to it (boosting the Surveillance Center by 2) to try and get your crime back down on that high-crime world, if desirable.

3. The main strength of the Xeloxi is their ability to spread crime to other civs, thus sabotaging their economy and penalizing their morale and production, using their exclusive "Look The Other Way" policy and their command ships.

This is actually the true purpose and main strength of the crime lord faction.  The description for "Look The Other Way" reads as follows:  "+20% crime, crime is spread through trade routes."  This is a pretty vague description.  This is what this policy actually does:

1. Gives +10% crime to all of your worlds (core and colonies)

2. Gives +10% crime to any opponent world that you trade with, at the rate of +10% crime per trade route.

Note that crime spreads from colonies TO a core world, therefore adding crime to a core world or any of its colonies will raise crime for that core world.  Thus trading with the core world AND its colonies will quickly elevate that world to very high, undesirable crime rates.  For example, an enemy AI civ starts as the Terran Alliance in their system with Earth and 2 colonies (Mars and Artemis), so 3 worlds total.  Let's say they have a crime rate of 10%.  You can use Savvot's shipyard to establish a trade route with all 3 worlds in that system, thus effectively adding +30% crime to Earth's system.  If you have a second shipyard somewhere, you can repeat this process to add another 30%.  If you had three shipyards, each establishing a trade route with all 3 Earth system worlds, then you would be adding +90% crime purely through trade.  This is not to mention the ability to bring an early command ship into the area to add the cherry on top.

This will impact Earth's system in a number of negative ways.  First, their decay rates will increase for all colonies, hurting all resource stats.  Second, economic penalties will be severe, and the wealth that the system produces will be slashed (this technique is thus especially desirable for targeting high-wealth systems).  Third, the civ will suffer a major morale penalty on that core world if you get the rate high enough.  Morale is penalized as follows: 

>30% crime = -2% approval,  >40% crime = -6% approval, >60% crime = -14% approval, >90% crime = -34% approval

As you can see, hitting a world to above 90% crime passes a major approval penalty threshold.  Fourth and finally, if the world is still growing, this will drastically increase the chance that new citizens are born as criminals, thus persisting this crime dilemma even if they rid themselves of your trade.

Some important notes with this policy:

- You do NOT want to have this active when the game starts.  It adds +10 crime to each world, and since Savvot starts with 2 colonies, this will blitz your homeworld with +30% crime (which does nothing besides tank your great starting gold income) and gives NO benefits (since you didn't start trading yet).  Only activate this once you have enough trade routes established to get benefits out of the crime spread, and you are prepared to handle or reduce the crime increase that occurs.

- Activating this WILL negatively hurt your economy.  No matter how your economy is structured, adding +10 crime to each world will instantly lower income across the board.  Only activate this once you can tolerate this impact.

- All Xeloxi command ships add +10% crime to enemy worlds in their radius (this does apply to each world in a system if you can fit multiple worlds in the ship radius).  If you supplement the addition of crime spreading by parking one of your command ships outside their planets, make sure to have an Open Borders treaty with that civ.  Otherwise they will very quickly dislike you even more than they already did, and you will be soon for war.

4. Xeloxi are a trade-centric civ, and benefit greatly from focusing heavily on trade.

The Xeloxi should revolve heavily around a trade-based economy and playstyle, and there are a number of reasons for this.

1. Trade is NOT directly impacted by crime rate.  Since Xeloxi have higher crime rates than other civs, it makes sense to try and base the majority of their economy around income that won't be negatively impacted by it.

2. Xeloxi start with extra ship range with their "explorers" civ trait.  This is common for trading civs, as it allows their vessels to reach trade partners located further away.

3. Xeloxi start allied with pirates, so pirates will not attack your trade ships.  This makes it a bit safer to send out unguarded cargo vessels to reach distant trade partners, particularly through the fog.  They are still vulnerable to things like space monsters, but this makes it easier to spam out far-reaching trade ships more safely than most other civs.

4. Trade is the key mechanic allowing their signature "Look The Other Way" policy to work properly, as described in the previous section.

5. Xeloxi are unlikeable, and most civs will quickly get mad at you.  Establishing trade routes gives the "We are trading with each other" diplomacy bonus, helping to offset this penalty a bit.

6. (Bonus): Thematically, this makes sense.  Criminal organizations are well-known for their smuggling operations, and Crime Lord civ would likely have lots of smuggling vessels roaming around to facilitate the illicit operation.

The more your economy becomes dependent on trade, the less you have to worry about your high crime rates.  You can even start to ignore high crime on income worlds once you have tons of trade, since their contributions to your income will be lower than the amount you get from trade.

Once you have all the trade research finished, you will have like 40 available trade routes (plus trader citizens, which can provide more).  This will easily allow you to fulfil the "crime-attack" scenario on certain systems as I outlined in the third section above.  It takes 7-8 trade routes to a system, plus a command ship, plus their inherent crime, to raise a system to 100%.  Having like 40 trade routes allows you to "crime-attack" multiple systems up to 100%, while maintaining a very strong, crime-proof economy of your own.

Once you have a trade empire, you will routinely have your own systems with 20%-60% crime on each of your worlds (which again, is not great, but not as bad for Xeloxi as other civs) - meanwhile several enemy systems will have a straight up 100% crime rate, causing income and decay problems, as well as morale issues which impacts overall production.

5. Xeloxi can effectively use portions of the "Secrecy" ideology tree

Xeloxi start with 2 awareness in Liberty and Pragmatism, so you can base your playstyle through those if you'd like.  However, they have a starting 4 awareness for "Secrecy" as their primary trait.  Yet again, Secrecy is a much-maligned ideology, further contributing to Xeloxi's low tier reputation.  It has some niche, if not useless, perks, and it is often difficult to build awareness for.  But, the Xeloxi have some synergies that are worth noting:

1. Silvertongue gives +5 deception and the "advocate" perk to all leaders, which helps facilitate culture flips.

- Depending on how you feel about the deception stat in general, this can seem useless.  Though Xeloxi do start with max "Deceptive" trait, so this does technically synergize.  However, late game, the Xeloxi have reason to invest in culture (their 3rd crime-specific building requires culture research).  So you may find yourself pushing over culture boundaries in the mid-late game.  Giving an advocate diplomat to an opposing civ will help your culture take over their planets.  It's a small potential synergy, but worth noting.

2. Criminal ties makes you allied with pirates

- Currently there is NO reason for Xeloxi to get this.  They already start allied with Pirates.  This is a waste.

3. Darkness gives enemy ships in our borders -1 sensor range and moves

- This is a pretty great one for Xeloxi.  As mentioned above, you often build into culture late game.  This expands your borders, giving you more territory for this perk to be active.  Also, Xeloxi are unlikeable, so despite your best efforts, some civs will take you to war.  Fighting off an invasion is much easier with this perk active, especially early.

4. Paranoia gives all leaders "Paranoid", which recycles them into your pool if your world is conquered

- Situational, but very useful if your inherent dislike and an unfortunate proximity to hostile civs gets you in early wars you cant outright win.  Ideally you don't want this or need this, but it does it's purpose very well if you do find yourself in an early multi-war position.  This, plus darkness, plus Xeloxi's very high resolve stat (more on this in section 6) makes you very hard to conquer.

5. Crime Lords gives 3 leaders and +3% global crime

- Again, to be clear, THE BONUS TO CRIME IS A BAD THING.  Xeloxi, however, can absorb this impact more readily than any other civ since they ignore moral penalties, and 3 instant leaders is always great.

6. Hidden Agenda

- This is really the key synergy.  I already described the Xeloxi desire to create a trading empire.  Yet they are also disliked.  And as we all know, the downside to a trade economy is that when that civ declares war, you instantly lose all those routes, the income, and the effort it took to establish them.  So how can you reliably establish a trade empire when civs dislike you?  In addition to the normal diplomacy-moderating tactics in the game to try and prevent war, this perk gives you a free 50-turn window to establish and reap the benefits of a large trade empire.

You can use Hidden Agenda to give yourself an immunity window to build up wealth and spread crime, and then after that window, if a civ takes you to war, you can use the "Crime Lords" trait to instantly get leaders to populate your command ships to fight the war.  Meanwhile, start making replacement trade ships for the next civ you plan to victimize.  Also as your 50 turn window comes to a close, you can try and use the wealth you accumulated to buy "non-aggression pacts" with some of your trade partners, buying you another 50 turns.

This may not be the strongest ideology tree, and even the Xeloxi may have better options, but it does work quite well with them, and their natural Secrecy awareness makes it easier for them to reach Crime Lords and Hidden Agenda at timely moments than other civs.

6. Other Xeloxi tips, observations, and recommendations

1. One of their starting command ships is a survey ship.  Many other civs have this, but don't forget to take advantage of that early extra survey ship that levels itself until you need it for crime spreading or combat.

2. Xeloxi struggle with food early.  Their home world Savvot only starts with 9 food (which is good for a random world, but poor for a homeworld - compare it to Earth's 12 for example).  Furthermore, Savvot is a desert with few tiles available for food.  Keep this in mind as you expand, as if you don't find a good food world soon, this will become a big limiting factor for your empire.

3. Xeloxi citizens have +10% approval for desert planets.  You may encounter another planet that qualifies, but for the most part, this simply means you have a nice little +10% approval bonus on their home world.

4. Xeloxi citizens have good stats to compensate for all being criminals.  Xeloxi citizens have high intelligence (+2 to base intelligence for all citizens, surpassed only by Iconians and Navigators), and very high resolve (+3 to base resolve for all citizens, tied only by the Drengin), and their citizens have no stat penalties.  Although they have no inherent research bonuses, they can get great use out of scientists with their high intelligence values.  Resolve helps with their average commander strength for their ships, and it makes their worlds take a very long time to conquer since citizen resolve values add to resistance. 

5. The conquering time from the citizen resolve, combined with the secrecy perks Darkness and Paranoia, make Xeloxi super hard to conquer by combat early.  It also means that if you have a core world system that happens to be maybe-a-little-bit-too-far-away, and if it comes under attack from hostile forces, those forces run into some problems.  It will take them forever to capture the planet, and when your reinforcements finally get there to capture it back, you can recycle your Paranoid governor.

6. The Xeloxi have access to the exclusive "Cutter's Guild" faction for leaders (Thanks to user Arcean_Endgame for pointing this out in the comments).  This raises overall production based on the members' Resolve (which as pointed out above, is quite high for Xeloxi citizens) and increases crime based on the members' Social.  This is a nice way to boost production, since Xeloxi are predisposed to absorbing the crime increase.

7. Remember that Xeloxi have the "Warriors" ability, giving them 10% bonus damage and damage reduction for their ships.  Due to their low likeability, they are likely to get into early wars with aggressive civs or even peaceful ones if you ignore diplomacy.  This ability means they are quite capable of fighting back if they have to, and you can even play them as an aggressive war-faring civ with this bonus.

8. When you start the game, you can activate the "Look The Other Way" policy JUST TEMPORARILY to get Savvot above the 30% threshold (which it should reach once it has both of its colonies).  Queue up the smugglers port, then take "Look The Other Way" off to get crime back down.  This gives you early access to the great Smuggler's Port building on an income-centric world, while keeping crime down.

9. When you take over enemy civ colonies, be wary that their non-Xeloxi colonists will still take penalties to morale for high crime.  A world exclusively made of foreign citizens will have lower crime anyway (since there are no Xeloxi criminals adding to the tab), but a Xeloxi world with 1 or 2 random foreign citizens will likely see them have an approval reduction from the crime.  This can also cause them to trigger negative high-crime events that you have to deal with.  Keep this in mind when managing citizens.

10. Similarly to item 9, if an opposing civ conquers your worlds, they have to deal with the Xeloxi citizens all being criminals to potentially impact the morale of their other citizens.  Furthermore, opposing civs will be much less equipped to tolerate high-crime worlds made up of those Xeloxi citizens.

11. Although the Xeloxi do not have any innate awareness for "Compassion" ideology, it also synergizes quite well by patching up some very specific Xeloxi weaknesses.  The compassion ideology tree can help entirely offset the downside to "Look The Other Way" by reducing crime by 10% with "Charity", as well as compensate for their starting negative diplomacy with "Kindness" and "Humility" (thanks to users Arakuel and Tid242 for pointing this out in the comments).  Even Crime Lords can show a little compassion sometimes.

12. Xeloxi are allied with pirates, so instead of fighting and killing them, you can use control points to enlist them.  "Enlist Pirate Fleet" allows you to gain control of rogue pirate combat vessels for 15 control points.  When you conquer all of the core worlds belonging to an enemy civ, if they had any colonies leftover, those colonies become pirate-owned planets.  These planets can be gained by using "Enlist Pirate World" for 30 control points.

7. UI glitch with crime spread through trade

It is possible that, even if you have "Look The Other Way" active, you may establish a new trade route, end your turn, then watch in dismay as that enemy planet does NOT increase in crime.  I do not know if the crime is not actually spreading, or if it spreads but just doesn't tell you by updating the UI.  Either way, this is the fix:

Any time you take "Look The Other Way" off, then immediately put it back on (even during the same turn), when you end the turn all numbers will update properly.  So if you notice new trade routes aren't registering increased crime, all you have to do is un-assign then IMMEDIATELY re-assign "Look The Other Way" before ending your turn.  I don't know what causes this glitch, but I have reported it in the bug report forums.

Final Thoughts

These are just my early impressions and experiences with the Xeloxi.  As I get more experienced, I will update this guide with more information.  I will also try to keep it updated through patches if anything changes.  It is very fun to run a crime syndicate and witness multiple enemy systems reach 100% crime. 

They aren't without their downsides of course. After all, blitzing an opponent with crime does give them tons of trade routes to benefit from - it is hard to measure the full impact of the morale/income penalties you impose.  Yeah your citizens are immune to crime morale penalties, but you have constant crime throughout your empire impacting income.  And while their home world has great starting income, it doesn't have anything else to write home about.  Setting up a trade empire is hard when everyone hates you, and a war declaration erases several turns of trade-route setup.  Are they low tier?  That is for philosophers wiser than me to debate.

I just wanted to clear up some common misconceptions and mistakes I see with this civ.  Hopefully this will encourage more people to try them out, and discover some tactics and synergies even better than those that I've listed, and share them with us through the forums.