This is the first that I've heard of this, please explain how West Virginia is an illegal state
States cannot be created from a state without the permission of the state. West Virginia was created from counties in Virginia that refused to seceed from teh Union. After the war, Congress then declared it a new state, without the permission of the citizens of the state of Virginia.
Hence, it is an illegal state.
Ok.. so it's an artificial state,
No, it is real. Adverse possession. But it is illegal.