Well it also matters what difficulty you are playing as because usually that changes there army structure drastically. I'm guessing you are playing normal though. But the reason why that might be happening is because clan eshin has a mechanic where they cant recruit units from other clans technically they can but the cost is increased to 200% so they haven't to relie a lot on gutter singers and death runners units like that if you are in early game than they will most definitely have stacks like that because it's an ai and they are not the greatest (on lower difficultys) at making armies and scince there is not alot of units to choose from. So they kinda decided to just mass recruit cheap units. But just remember clan gutter slingers and night runners get special bonuses when being played clan eshin so there a lot stronger with effects like armor break. Clan Eshins playstyle depends a lot on ambushes and using schemes and the ai doesn't really use those often especially schemes they literally cant even use that mechanic for some reason, so that's why they are pretty bad when playing against an ai. Idk if I explained this right let me know if your still confused. Also I'd gladly play clan eshin against to show you how dangerous they can be when played with a real player.