Glad to hear you enjoy it!
A couple of considerations:
- You could keep track of the orc's inventory and keep Fatigue in line with that, reinforcing the idea that NPCs are really the same as PCs
- You could give NPCs 1, 1d4, 1d6 or even 1d8 empty slots to fill with Fatigue, as a way to quickly scale it.
- But, most likely: give them functionally-infinite fatigue, because I personally had very few fights last more than 3 rounds. This stuff is *lethal*, so long-term Fatigue tracking for NPCs hasn't really come into effect yet on my end :)