basically a skill tree for generals with upgrades like
1) transfer speed
2) travelling speed
3) bonus points to certain troops (either attack or health)
4) possibility of finding loot in camps that have been destroyed in %
5) recovery time
6) generals attack damage increase
7) super skill can cross one montain or river or something like that (1 per adventure no matter how many generals are upgraded)
8) super skill stealth can bypass 1 red zone (1 per adventure no matter how many generals are upgraded)
9) super skill double troops 1 time attack but recovery time even with victory
and as a side note an empty troops button would be so handy also some sort of visibility improvement when the general is hidden in the trees and mountains