The Eminence in Shadow, Vol. 13 (manga)

Cid and Beta have arrived at one of the last places the aspiring shadowbroker wanted to go—his former home world, Earth! Or what’s left of it, at least. Why’s everything in ruins anyway? It doesn’t really matter, because Cid has a bigger problem: If Beta works out that his vaunted Shadow Wisdom is all normal stuff any earthling would know, he’ll look seriously uncool! He’s gotta find a way back to his rad isekai fantasy life while she’s still in the dark, but little does he realize that his boring old planet’s got some brand-new thrills…!