Combatants Will Be Dispatched!, Vol. 4 (manga)

A month has passed since the cease-fire with the Demon Army, and with the teleporter online, Kisaragi has sent a mutant to help this invasion get back on track. But their plans are derailed once again when Six is dispatched on a diplomatic mission to Toris for water crystals that will relieve the kingdom of Grace from its terrible drought, a problem he caused in the first place by changing the rain-making artifacts password to something that cant be printed on the back of a book. Is Six really the right man for the job...?