User blog comment:Caudyr/Abilities List From the Author + Translation of Abilities as I go Through the Story.../@comment-24863069-20151112143601/@comment-4784862-20151112193843

Trolls and ogres are indeed in the Giant category...but that doesn't mean they aren't ALSO in the Demonkin category. There can be multiple categories...as iirc the Cyclops is considered both a demon AND a giant.

That said, yeah...from what I read, Demonkin is intended to be more or less for demihuman species of the "Demon" class. As in...Lords, Goblins, etc. It's reasonable to assume he can summon Ogres with this ability, though...since it's from the same evolutionary path that he is from.

Has he summoned Orcs and Kobolds with it? It would make sense, but I don't know if anything like that was confirmed. I'm not even certain what he learned this from, tbh...since I haven't gotten that far, yet. XD

As for the "Fiend" thing...it's for actual demons. IIRC he uses this ability to summon the Taurus Demon he got the abilities from the day before.

TBH, though...the main reason I went with Fiend over Devil or something like that in this case...was because the abilities were synthesized into the umbrella ability...and I thought Archfiend sounded amazing compared to the other possibilities. XD