No Game No Life (2014)

S1E7 Sacrifice

The siblings aim to take on the Werebeasts, but crafting a winning plan proves tough since every challenger’s memories of the games have been wiped clean. Their progress stalls until Stephanie hands Sora a key once owned by the late king. That key unlocks the former ruler’s hidden research, which holds the secrets to outsmarting the Werebeasts and turning the tide in their favor.