Leviathan is a oNA (web) anime that premiered in summer 2025, produced by Orange.

About the production: the story comes from a other, there are 12 episodes of about 25 minutes and its current status is "finished".

Its main genres are adventure, mecha and sci-fi, with themes such as Aviation, War, Steampunk and Military.

On AniList, Leviathan has an average score of 66%, a good score, and appears on 6,938 users' lists.

Set in a war-torn reimagining of 1914, Leviathan follows Alek, a fugitive prince of the Austro-Hungarian Empire, and Deryn Sharp, a daring young girl disguised as a boy to serve in the British Air Service. When fate throws them together aboard the HMS Leviathan, a massive, living airship made from genetically engineered creatures, they embark on a world-changing adventure that will challenge everything they know about war, loyalty, and identity. (Source: Netflix)

Official synopsis from AniList.