No Game, No Life Episode 7: Sacrifice
Episode 7 of 12 of No Game, No Life, aired May 21, 2014, 25 minutes. Available with English subtitles and dub where released.
Episode summary
Intending to challenge the Werebeasts, the siblings discover that it's hard to come with a strategy to defeat the latter, as all memories regarding the games are erased from their challengers, until Stephanie entrusts Sora a key left by the former king, leading to his secret research on how to outwit them.