When played in combat, an opposing thief champion is defeated and sent to the abyss.
Copyrights:
TSR
Wizards of the Coast
In most 55 card tournaments, it seems most people are obsessed with instant kill cards. This is one making it at least a thought for a tourney deck, or at least for a bigger deck battle (like 75 or 110 card settings). Plus, the addition of sending that champion to the Abyss is very nice.
However, thieves are not the most combative class of champions usually. It's their assisting cards that makes them so nasty. While I could definitely see this card having a place in a deck focused on attacking champions in the pool (using cards like the Arena of Dori the Barbarian (3/IQ) or Throne of the Drow (468/4th)), I'm not sure I would put it in most tourney decks.
It would definitely see more use in fun games, except people tend to target players who win using just instant killers by just blowing up their realms. Plus, this card is useless against a non-thief (+1 bonus is practically nothing).
Overall, unless you've got a great stategy to just attack specific champions, I wouldn't use this card in most games.