Troops is a common term used for units that aren't commanders.
A ruler can promote a troop to the position of Warlord. This seems to be uncommon. Some possible reasons for this rarity:
- High minimum level requirement few troops reach
- Troop type restrictions (Men only?)
- Maximum current warlord limit (a side may only promote when they have <X warlords or <Y commanders?)
- Promoted warlords are generally infrerior to popped ones