Sword Art Online: Alicization Episode 12: The Sage of the Library
Episode 12 of 24 of Sword Art Online: Alicization, aired December 22, 2018, 25 minutes. Available with English subtitles and dub where released.
Episode summary
Kirito and Eugeo escape from their cell, only to find their way blocked by Eldrie Synthesis Thirty-One, under orders from Alice to lie in wait for them. Kirito and Eugeo struggle against him until Eugeo realizes that he’s seen Eldrie somewhere before.