I'm not sure why, but it seemed to take a lot longer to get to level 12 with Rilly than with the other characters. Sometimes, it seemed like I was dying more frequently. Certainly more often than I would expect with a demon pet soaking up damage. I don't know, maybe I'm just so used to melee combat that I want a warlock to blow things up quicker.
I'm rather curious to see how long it will take Rilly to hit level 14.