[Shade Genkai]

The only other skill that comes to mind that I'd likely have involve an interaction with souls in some way would likely be the matador rage functionality of the Demon Hunter class; the rage energy itself being stored in an attached soul in order to be expended later in battle for attacks. I may choose not to do that, however, as I'm more partial to the idea of the souls not being capable of directly acting on the living and instead focusing on things inherently difficult to explain like the two skills already mentioned, and I don't believe there are any more like that in the character's kit.

As for the matter of antagonism.

It's not my intention to be actively antagonistic, but instead to be a target for antagonism by those who would have a problem with the use of this particular technique. A certain exorcist duo in Korvara come to mind as an example. Effectively it's intended as something of a negative rp hook to provide tension in random encounters and in personal plot.

What the character mostly intends is to legitimately use this technique for business ventures such as selling souls to people that want to make Homunculi or people doing research into spiritual or occult matters. . . or anyone that wants a soul for whatever reason, they're not exactly a morally sound person. I could see people learning from the character, or just figuring out on their own, how to use the souls they have to fuel their own esoteric skills like Steal and Negotiate. Bearing the approval of their own applications in those cases should the need arise, of course.

Even despite that though there are more mundane uses I could see coming to pass.

Families that have knowledge intended to be passed down generation could hire the character to bind the soul of a member of the family so that those later down the line could refer to them for knowledge after they've passed; from the other direction, someone who wanted to continue to serve or assist another person after their death could request a contract be made that would allow them to do such as a soul. Both of these examples, as well as likely any other that would involve this ability, would require the clientelle and any other involved party to be able to have spiritual sensitivity in their own right, of course.

I mean, unless they for some reason are fully willing to believe that this person is doing what they say they're doing without external proof.

Some -actual- antagonism I could see coming to pass is the character blackmailing someone they will eventually gain the soul of who is also particularly invested in the integrity of their soul's fate. Since there is the possibility to trick someone into a contract (IC'ly only, as mentioned above OOC understanding and consent is a necessity, both just for keeping things on the up and up and to prevent confusion down the line). In those instances though the binding technique is more a means to an end as opposed to the direct source of the antagonism, it still requires someone who both cares about their soul and can be made to comply to whatever is intended of them. Since the 'ownership' of the soul transfers only after death and there's no way for the bound souls to truly interact outside of communication or utilization by those that own them in already OOC'ly approved techniques or methods.