I don't think your companions could actually leave in D:OS2, they'd just fuck you over in the endgame if they didn't like you.
Oh! That's even worse! I've never played D:OS2 so this is news to me.
The DOS2 endgame was about who got to ascend to Godhood, and it was made clear by the mid-game that only one in the party could do it. So there was a sort of background mechanic at work, where companions could secretly be working against you.
