Rao is an older man on a mission to liberate Sand Land from its tyrannical king's control. He's best known as the former General Shiba, though he vanished years ago after leading forces into a disastrous operation—one the king had ordered him to execute. His troops were decimated trying to destroy what he believed was a dangerous weapon.
The truth, though, hit him hard: that "weapon" was actually a water-producing machine. Realizing he'd been manipulated into mass destruction, Rao became determined to make things right. He travels alongside Beelzebub and Thief, and together they work to topple the king while trying to help the families devastated by the deaths his orders caused. It's less about redemption in the traditional sense and more about actually fixing what he was tricked into breaking.
Content compiled by AnimeList.moe from publicly available sources.
