[. . .] Jesus didn't look any different than the rest of the people he was around, right?
That depends on who you ask. The thing is, we don't have any book-related evidence supporting this being Ruin's body, and we do have (Albeit rather flimsy) book evidence supporting this being an Inquisitor. Though just to play devil's advocate, I will mention that if this particular keeper-sacrifice would grant the Hemalurgist below Feruchemy as well, then I could see Ruin taking someone who has all three magic systems as a body. However, I'm going to stick with my original assumption that this is an Inquisitor for the simple reason that Ruin could already control Inquisitors. If he has complete control over them, why would he need to take one of their bodies? It would just seem to me like that would decrease his options, as he could either
A. Make a new Hemalurgist and (possibly) place himself in the body, or
B. Make a new Hemalurgist and control it do do his bidding while he does more omnipotent things.
I don't see much sense in him making himself a body when he could just control it anyways.