Galanar
David said that everyone that took Solomon's legacy got corrupted and/or died to it. I expect this is what we are seeing here, albeit at a much slower rate due to his power or.affinity. More than likely melding with demons doesn't help and may even accelerate the process as they infect him.I expect we go on to have this be cured, or at the very least see him start to control this corrupted side of himself and I look forward to seeing it happen if that's the case.
Galanar:Keep in mind his first bit of corruption also didn't come from the legacy at all. It predates even meeting half the people he knows now XD