Anyways, on the concern of Ace Arknight's race being either Pythia, Zalak, or Savra. tl;dr, it's most likely Pythia or Savra, or a Race we have no knowledge of yet, more below.
Don't quote me on any of this and be more than welcome to correct me in any matter.
Anyways, of the three Races that Ace could possibly of, we first need to find out how to indicate what race belongs to what race. Let's start with-
Zalaks, they're the Rodents and Rodent-Like, important on the latter. They're the Rats, squirrels, and apparently the Australasian Opposums.
Next is the Savra, Lizards and Salamanders. Which in itself is completely different from the-
Pythia, as these ones are the Serpents, Snakes, basically. Why are there no Gator's or Crocs in either of the Reptile Races? That's cuz those are the Archosauria.
Now, what are these three's physical indicators of which they belong to? Well, for the all of the one's mentioned above. The ears, tails, and their Operator Files. But Ace doesn't have a File that says what his race is so we can only go with the former two.
Zalaks have rodent-like tails, duh, take a look basically. A detail that every race with ears on the top of their head has is that they wear Helmets that fit them or have holes for them, like Ashlock and Click here. You can also notice the variety in that one has a ridiculously Fluffy tail, and one a sleek and thin one. There's also the Rat King who's a fully formed Anthro, but he's not relevant here other than being a full on indicator that he's a fucking Rodent.
Now, if we compare that to these-
-he does not have any furry ears on the top of his head, this eliminates him from being a Zalak, as if he was one, then he'd have something that wouldn't. And no, I've checked every Zalak that's been illustrated, and they ALWAYS have fully visible furry ears or Indicate that they have them through their helmets or headgear.
"But what if there's Zalaks that DON'T have furry ears?" That's a possibility yes, especially when you look at the Anaty and notice how Roberta and Mayer don't have ears compared to that of Robin and Shirayuki. If it wasn't for a teensy little weensy detail about Ace's tail.
The Tip. No Zalak's have tail tips like these, as a Zalak tail's tip that are slim usually resemble that of diminishing lines, more so a whip than a tip really. At least of my knowledge and quick 5 minutes google search (Lmao) If you do know, please do tell.
Though there is the Rat King's, but if you look it's still not the same, as Rat King's resemble that a, well, Rat. While Ace's look that more of a Lizard's. There's also the Age Factor, as Zalak that has Ace's look of an old veteran would be equivalent to that look.
Speaking of Lizards, let's get into the them.
Now, for Savras it gets a little trickier, as of the only fully illustrated characters that don't help much to identifying someone's race through their ears and tails is the two anthros, a Half Savra-Sarkaz, and a Hooded NPC, that obscures both the ears and the possible tail, who we can only assume Savra for the same reason I assume Sharp is a Savra. By being from Sargon, except Isin lives and breathes Sargon while all we know of Sharp is that he was from the Court of Sargon before he came to RI.
Getting back on track, Savra's distinct traits are that of Sharp Ears and Reptile Tiles.
But, if we look at the patterns of the one's with the visible ears and tails, we can see the Savras usually have thicker tail and pointy ears, which overlap with Pythia's also having sharp and pointy ears. But it's important to note that Pythia ears are several times Sharper, and their Tails far thinner.
But there's also Pythia's such as Corroserum and Eunectes who's tails are quite thick themselves. However, their thick tails are scaled compared to the Savra's just up avove.
Though the ears is a good point to look into, as Blacknight, a Savra, for example can pass off as a Pythia if you look only at the ears alone, but then look at her tail and think maybe Archosauria. If it wasn't for her Animal being indicated by her E2 as well as the Profile saying so, we could've safely assumed she was a Half and Half of Pythia and Archosauria. Probably something along the lines of a Black Caiman.
So, what do we get from this?
Well,
Ace can't be any of the non reptilian races. Or any race with ears on the top. No his portrait is not showing them because he has them folded back, look at new visual from the anime and you can see he has nothing up there than hair.
Not Archosaurian, as there is no way his tail is in any way Crocodilian.
We can't use his ears as confirmation because they're covered, and even then the ear shapes can still overlap.
His tail is thin and definitely belongs to a Reptile, but no obvious scales, nor that obvious a salamander or Lizardy. BUT, We also have to keep in mind that Scaleless Snakes EXIST so we can't immediately rule it out.
So in conclusion, I don't fucking know
What i do know is that this bitch a reptile. He could be some Scaleless Snake species idk about, or a Glass Lizard which means he's either a Pythia or Savra
My bet would be Savra more than Pythia
Addendums:
Checked the Prelude to Dawn PVs, nothing on Ace's Race Features.
There's a non zero chance that the Race Ace belongs to is a mythological inspired one like Hellagur, Utage, and Archetto are.
