Man made race.

[Cilia]

Well they were supposed to be this sci-fi uptopian socitity before their fall, which means that had access to lots of advanced tech. Plus we have confirmation of cloning, so it's likely that they started from there.

Well yeah, but when you think about "demon" (which may as well be a synonym for voidsent), it's generally possessed of a special essence that separates it from normal life-forms. Sure it's possible to replicate the physical form, but without an infernal spark, it's just a fake, like the difference between Echidna and various lamiae that inhabit Azys Lla (etc).

In regards to man-made races being playable in the future, with the tech we have now I'd expect to see something like the Warforged from Dungeons and Dragons' Eberron setting. While it took a considerable amount of effort, we've already synthesized a sentient soul. Unfortunately, considering how expensive the items just to make a weapon to house our Anima weapon's spirit is, making a fully-functional humanoid frame is out of the question except for all but the wealthiest people in the game story-wise (Rowena and Lolorito, basically), and those particular individuals are unlikely to make such a being out of the goodness of their hearts.

(Yes, like many people I am quite salty over the exorbitant amount of effort required to get an Anima weapon.)