>>Therefore, what fits your story better? An ancient Antichrist or a recent one?
I'm not sure what you mean.
Connor is (supposedly) in hypostatic union with God (the Son) as is Jesus. In my story, the AC didn't exist prior to the birth of the little demon-spawn. In Connor's case, he'd be claiming to have been in hypostatic union with the Son since Connor's birth. Although his soul is ancient (Adam), that element of Connor's existence isn't revealed until the very end of book one (with Adam's identity revealed to Connor at the end of book 2). When he's attacked in the Church of the Holy Sepulcher, it supposedly gives him access to the Son's "memories", which would include those of Jesus. Indeed, the whole time they're in the Holy Land, he'll seem to experience snippets of Jesus's life as the tour group moves from site to site (the same as he did in the first draft). Ostensibly, the reason he experiences these is because he's in union with the Son, who is in union with Christ.
Even as I wrote about Adam in the above paragraph, I realized that means Connor, who is physically just 14 years old, will claim to be the 2nd incarnation of God, in hypostatic union with the Son (for those past 14 years) and indirectly also with Christ, but Connor's soul once belonged to Adam. If that doesn't make your head spin, I don't know what will. :-) Fortunately, he will have ceased pretending to be the 2nd incarnation around the latter half of book 2, and he'll learn about Adam at the climax of book 2.