Undefeated Bahamut Chronicle (最弱無敗の神装機竜, Saijaku Muhai no Bahamut) is a Japanese light novel series, written by Senri Akatsuki and illustrated by Ayumu Kasuga. SB Creative has published six volumes since August 12, 2013 under their GA Bunko imprint. A manga adaptation written by Itsuki Watanabe, with art by Fumi Tadauri, began serialization in Square Enix and GA Bunko's online magazine Gangan GA from 2014.