User blog comment:AquilaeAltair/OnS Theories (5S) - Third Theory - Rigr’s weapon: An incomplete seraph/@comment-36009152-20190820011538

Comparing Saito to Urd, the former came across as more lively and even now seems like someone who is filled with life – both a passion to see the first fall, and retaining some human traits like joy. Wonder if Saito had something seraph related transferred to him which put a stop to the vampire effects of subduing feelings?

Your theory says as much, and Saito gaining the powers of an original one, rather than a seraph achieved through experimentation is more than likely with his closeness to Sika Madu. As for the part about Saito not being able to turn into a seraph unless someone turns him into a human again, he seems to be becoming at the every least less vampire like and can also manage seraph grade powers as well as he is right now! No idea if it’s because he’s restoring his humanity, or still a vampire and accessing these powers anyway, in any case he's still able to make use of them.

Bear in mind a lot of Saito’s comments are diversions and backhanded, like saying his impressive beasts are just smoke and mirrors though in reality capable of diving straight into the first's scythes and apparently being able to piece the first as well.

Yes, Saito saying the first’s wings are lovely as always, like an angels can pretty much be confirmed as being sarcastic XD basically saying they are not lovely, and just like an angels meant to be mocking because the first is certainly not that… Saito on the other hand…

All in all, evidently quite the joker, and all this to make Shikama Doji see him again? Well that's what Saito said! Whether it is really the case though, who can say at this point.

Do agree, with the battle ongoing the full extent of Saito’s power is still yet to be shown. Must be seraph related, demons and vampires certainly are not tools to use against the first. What is more he has a seraph in Mirai over in his corner as well so evidently invested in seraphs!