I don't know how the idea of corruption came up, but it's a pleasant surprise.
Of all the new domains he could have learned, I would never have thought of it.
This one seems to be made to torture his enemies unlike the other two.👾👾
Unexpected indeed. I guess it has to do with his mysterious bloodline and origins. Perhaps one his parents was an eldritch horror lol.
I still hope he manages to mostly recover before his trip.