An Archdemon's Dilemma: How to Love Your Elf Bride: Volume 18 by Fuminori Teshima

Zagan is making moves to resolve the many problems on his plate when his old friend and enemy, Marchosias, suddenly shows up and calls for a gathering of all Archdemons at the ends of the earth. Zagan decides to go, and since he’s going out anyway, he takes everyone on a sightseeing trip! Meanwhile, Barbatos appears to be plotting something involving Zagan and Nephy...