Software used : Adobe Photoshop
I've never heard of a private commission of an IP being a problem. Even when doing something as bold as selling prints at a con probably won't land you in hot water for the simple reason that you're operation is likely too small to notice and not worth the resources to stop even if someone cared to. For example, what would Blizzard ultimately be accomplishing by disallowing artists to create fantastic works like this? They lose no money and in fact ultimately gain free advertising. The only time this may fathomably be an issue is as if you become an "internet famous" NSFW artist whose work has an overt focus on a particular franchise. Even then only certain companies really care about how that may damage their brand image (*cough* ninetendo *cough*)
Thanks a lot! Yes, I love to take my time with this kind of pieces ^^
The subject is always a bit tricky but I think that as long as it stays "small" and that you are not really abusing their already compliant politic regarding fanart/commission, you should be fine.