So a mate of mine took control of a unique character that I controlled, then I played another of the same character. He later killed his version of the character for claim effect and then said my own version also died as there was a copy in my dead pile now.

I was under the impression the character would go to my discard pile or his dead pile. Where should it have gone?

So I found in FAQ it would go to dead pile. Would my own character die as soon as my opponent killed his own version and placed it in my dead pile?

Donnyb said:

That's your mistake right there. You can't play or put into play a card if another copy of that card that you own or control is already in play. You don't control your unique character anymore, but you still own it.

When a card leaves play, it always goes to its owner's out of play area, no matter who controlled it at the time it left play.

Donnyb said:

That's not correct either. If the situation should ever arise that a copy of a unique card enters your dead pile while you have another copy of that card in play (a very rare situation, but possible, e.g. with Aegon's Hill), that copy just stays in play normally.

Thanks very much! (post too short)

Donnyb said:

You're welcome! BTW, I noticed that I made a rather severe mistake in my post above:

The sentence "You can't play or put into play a card if another copy of that card that you own or control is already in play." should read "You can't play or put into play a unique card if another copy of that card that you own or control is already in play." I assume you inferred as much from context, but I wanted to make sure no misunderstandings arose.