Books in the Combatants Will Be Dispatched! (manga) series

Agent Six’s squad, having failed to get their hands on the water fruit after an attack from the Sand King, are stuck wandering the desert. It’s looking bad—they’re running out of water, their capacity for rational thought is boiling away, their “survival instincts” are starting to go off the charts, and their useless necromancer is shriveling up into nothing. In the face of all that, can Six and the rest make it back from the desert alive…?!