One of the rules I’ve instituted in my Stonehell game is that hirelings who survive slowly buildup some XP of their own, and if they survive often enough (around the 10 session mark) they level up into 1st level characters. While this increases the might of the party, it dilutes the XP that everyone gets, as each NPC character gets a half share of XP.
At this point, only a couple of NPCs have survived to make this leap.
A-A-Ron was the first. A poor torch bearer for the party, who ended up surviving numerous trips into Stonehell and even helped out in a massive battle in the Quiet Halls. Orpheus was similarly promoted, but as he’d been a man at arms rather than a torch bearer, he became a fighter. Both were done before I’d really formalized in my head a method for the transition. Also there was Yolanda who left the party after Wilhelm died, and founded her own adventuring team.
Darryl the priest was captured and pressed into service.
Brie came up as a random result from the Meatshields generator, and I came up with a backstory to match, and tied it into Yolanda’s story.
Next was Lex the Cheeseman, who like Orpheus has been a man at arms, and so became a fighter.
Most recently, Koltic was just promoted and he became an acolyte under Darryl the Dark. He had to give up his longsword for a mace, but now he can turn some minor undead and has a few extra hit points.
With this, the party now contains 6 NPC leveled characters, and 2 PCs.
Both Orpheus and A-A-Ron are loyal to Eiric, and I don’t see any reason for them to consider splitting off on their own. Darryl and Koltic? Less so, though still fairly loyal. Brie is entirely mercenary, and will stick around as long as she keeps having access to Eiric’s spell book and mentoring. Lex likes Orpheus, and has a snazzy magic weapon. So, honestly, at this point there isn’t any good reason for any of these NPCs to split off on their own at this point. If either Eiric or Karl dies, maybe then.
I do need to spend some time working out some outside the dungeon motivations for them though.
Darryl probably wants to expand his temple’s influence in town. Orpheus has his orphanage and dog kennel. A-A-Ron gets missions from the thieves guild, but at this point is probably will start to take over the guild if he can.