Fiendish patrons are also described as archdevil level.

Quote
You have made a pact with a fiend from the lower planes of existence, a being whose aims are evil, even if you strive against those aims. Such beings desire the corruption or destruction of all things, ultimately including you. Fiends powerful enough to forge a pact include demon lords such as Demogorgon, Orcus, Fraz'Urb-luu, and Baphomet; archdevils such as Asmodeus, Dispater, Mephistopheles, and Belial; pit fiends and balors that are especially mighty; and ultroloths and other lords of the yugoloths.

It's hard to imagine an archdevil being captured at Moonrise at such low level play. And Mizora seems more like some mid-tier Succubus at best which makes the whole thing even more weird. If she gets captured so easily she might also get killed just as easily. How does someone like that grant powers to mortals?

I think I would get the character better if he actually had a vengeful side against people (and not just goblins who took his eye), or was more antisocial or something to reflect the supposed abuse he's gotten and motivate a desperate pact for power. He's just acting too normal to have gone through anything of significance. Being a Warlock and making pacts with archdevils is a bit of a big deal, and I get the feeling Larian are completely downplaying the whole deal. While also not making the character at all mysterious (like Shadowheart) or likable (like Gale at his best) to let any kind of companionship to start forming. And when the player finds out about him basically being a lying loser who sold his soul to a devil, we are just expected to.. like him anyway?

Shouldn't a Warlock have strong convictions about something at least? Or is he just a desperate power hungry puppet for Mizora? Which would make him a bit of a poor companion choice if written properly rather than just conveniently sidelining the patron.