That's pretty cool magic. The warfare is like ritualized European warfare, where tactics amount to mobbing the enemy's mobbed mobs with more mob.
Perhaps we shall see this isekai MC invent the Dakka, and perhaps we will see something like the machine gun in Kuro no Maou... no, we probably will only see half-baked harem antics. I kinda want to see, for an change, a retarded MC whose harem is lost in brütal warfare that he loses just because he isn't an OP MC.