How to modify an npc's damage output

[SeraVerte]

How do mod authors make npcs stronger without altering their stats or giving them overpowered weapons?

I've installed a mod (I can't recall which one, but this isn't a specific instance) that somehow makes bandit marauders one shot my lvl 30 character on master, and 100 damage on my character with 300 armor on novice difficulty.

I checked the bandit's level and one handed skill and they were no different from vanilla bandit marauders, their weapons were no different too, so how do you modify an npc's damage on the creation kit?

Thanks.

[steve40]

On the Actor form, Attack Data tab, you can change the damage dealt by each different attack without changing the actor's level. But technically you are still changing stats.