Undefeated Bahamut Chronicle (最弱無敗の神装機竜 (バハムート), Saijaku Muhai no Bahamūto, lit. "Undefeated Weakest Bahamut") is a Japanese light novel series, written by Senri Akatsuki and illustrated by Ayumu Kasuga and Yuichi Murakami. SB Creative published twenty volumes from August 2013 to August 2020 under their GA Bunko imprint. A manga adaptation written by Itsuki Watanabe, with art by Fumi Tadauri, was serialized by Square Enix and GA Bunko's online magazine Gangan Online from July 2014 to May 2018. It has been collected in eleven tankōbon volumes. A 12-episode anime television series adaptation by Lerche aired from January to March 2016.