Diablo 2 shows examples of this. The VERY first early story boss in Act 1 is Blood Raven, who is the corrupted version of the Thief character you can play as in Diablo 1. The one Sorcerer boss you fight early in Act 2 is the Sorcerer character from, well, Diablo 1 again. And finally, Diablo 's host body, as The Dark Wanderer that your chasing all throughout Acts 1-4 is the very same Warrior character who tried to imprison Diablo in his own body(D1).
I don't think that's the same thing as what's being described though.
There's no evidence they were "tempted into evil" as seems to be being described, and that doesn't really make sense with D2's cosmology, rather explicitly they "brought back an evil presence", which is what I referred to re:
And Aidan, the Warrior it's clearly a case of:
proximity to Evil Magic Gems
What it's not is "Oh I decided to be evil for gain!" or similar.
Also,in Act 3 of Diablo 2, before fighting Mephisto, you come across the corrupted versions of the High Council members of the Zakarim Faith/Church that The D2 Paladin is a member of. They literally serve as mini boss obstacles as you make your way to Mephisto, the one who corrupted them.
No evidence whatsoever that they just decided to "turn evil" though. On the contrary it looks like Mephisto's power overwhelmed them.
This also matches up with how corruption is depicted in Diablo 3 and Diablo 4 - people don't just decide to be evil or w/e, they get overwhelmed.
In Act 5 of D2:Lord of Destruction, the one member of the Barbarian village, that serves as your hub, is betrayed by a member of that community and is a, by The Rathma faith, a corrupted Necromancer.
You mean Nihlathak from Harrogath? That's certainly the closest example, far closer than the rest, because he makes an actual conscious deal with Baal. He is 100% NOT a "corrupted Necromancer" though. Necromancers in Diablo lore are a specific sect from a specific place. He has Necromancer-style powers (but also a non-Necromancer ability), and is some kind of "raiser of undead", but Necromancers are holy warriors with a holy mission and a holy duty and we can't go around call random barbarian council members who know magic to raise the dead "Necromancers". He's also not really "corrupted" in the same sense at all, he's just evil. He shows no signs of having demonic powers, mutations, or influence, unlike the rest.
So corruption is a thing, but it's an external pressure usually directly from an extremely powerful supernatural being or a soulgem they're in or similar, or very rarely, some kind of formal betrayal deal (I think there's one in the D4 expansion also). People don't just like flip to the darkside because they had a bad time or got mad or w/e.
The other issue is that again, both sides in The Eternal Conflict are bad, but being excessively Angel-following doesn't seem to have the same effects. That said, there are plenty of fanatics in D4 who might provide some kind of model for that.