The more legitimacy you gain, the higher in tiers you go. T1 are typically given at very high legitimacy levels. So just keep conquering planets and you'll get one eventually. The first heroes you'll get will be a T5, then a T4, etc.... They'll just be picked at random from a pool of any legitimacy heroes not yet on the map at the appropriate tier(other imperial factions will also be gaining them, so it's kind of a competition with them to prevent them from getting one you want.)


You can still get more legitimacy heroes after getting a T1, but I think it's a bit more random which ones you get. Most of them are still worth having, even T5 heroes can be pretty nice.

Additionally, when you integrate a faction, any of their surviving heroes will join your faction as well. Warlord heroes themselves cannot be integrated, as they must be defeated in order to integrate a factions.

Your legitimacy score doesn't affect what legitimacy heroes you unlock or what tier you get access to. You will always unlock one from each tier first in order no matter what your score is, after that it will be random (Except for only ever getting a single tier 1 reward unlock).

A high score is what is necessary for faction integration. A defeated imperial faction will only join the faction with the highest legitimacy score.