I Became The Dark Side of The Hero's Party of My Own Volition And Was Cast Out for Being "Unnecessary", But We'll See About That

Hidden is a scout who joined the hero's party to defeat the Demon King. But the hero, Ashram, and his party members did not know anything about the fundraising, the spies sent by the Demon King, or the assassins sent by the rebels. Deciding to support from behind the scenes, he took on all of the dirty work for them. But his party members did not know about what he had done for them, and ended up casting him out of the party... With nowhere else to go, Hidden headed toward the dark guild.