I voted no.
The reason for that is that I simply assumed that you, being a DM on a RP server, don't mind a RP fight.
If people wanna beat something they can't beat, they can RP beating it, simple as that.
It does get slightly more involved when it's a player you want to beat up with RP, one who otherwise wouldn't loose to you, but I imagine that a DM would be willing to let others (within the sense of reason) get the upper hand when certain conditions had been outlined.
@Avatar6666:
1: Angels are, by their default description (biblical) actually contious of their actions and the choice of each one. That is how Lucifer/Satan/Belzebub (Or however that's spelled) came to be, in a biblical sense atleast.
Of course, the setting of Kymlun probably depicts angels far different from the biblical version, but this was one of the ways to answer the question.
2: (And god I feel like the pope when I fire off this answer) About the non-getting-slapped-by-good-alignment-devine-thingies; The ways of the heaven isn't for mortals to understand
Naa, just kidding. My proper answer would be that, as far as I understand, that said deadish-angel-character, aka Keldrin isn't an Angel, fallen or not, but with the Bloodline of Angels.
Technically a descendant of them in a way, or rather, the decendant of a agent of angels.
3: Casting with 1 hand; Still Spell would be a good guess.