Thanatos comes from the soundtrack of Neon Genesis Evangelion, the 1995 anime series created by Hideaki Anno and produced by Gainax and Tatsunoko. Composed by Shiro Sagisu, the piece was later included on the Evangelion soundtrack albums and is closely linked to the series' darker, introspective episodes and the 1997 film The End of Evangelion. Online, the cue has been reused for years in fan edits, AMVs and dramatic montages because its slow build signals tragedy and reflection without needing dialogue.