STAR RAILED

I am a sucker for angst and thus a firm proponent of the "Dan Heng had a tail" theory, with all of the fun and terrible implications. Since Dan Heng and Bailu are both the only "newborn" (in Vidyadhara terms lol) dragons that we have an example of, completely not following the standard high elder succession at all, I think it would be cool if Dan Heng and Bailu are actually more alike. (I have more headcanons for this specifically but that's a different post.) Also to make that "where's your tail" scene more impactful, hehe.

Anyway I hc that they were both born with solid horns, solid tail, and scales along their back. (Like how Lingsha has scales on her arms/legs and Dan Feng had scales ~somewhere~ if they were uhhhh removed.) His horns and scales were much lighter when he was born. (Like this, because Hoyo loves teasing us about that tail. I know this series ain't canon but )

And then started to gain a gradient and get dark as he got older, through ontogenetic color change. (Like what milk snakes and some other reptiles do.) Bailu should totally get the same gradient effect when she finally is able to grow, btw. It'll be cool. Anyway, this is definitely a factor in freaking the Preceptors out, because they took a risk in bypassing the proper ritual and hatching a reincarnation and calling him Imbibitor Lunae, so any non-standard traits are bad for their narrative.

Hence ultimately getting to the point where they team up with the Ten Lords have it removed for some bs reason. And they can't remove the horns, but they can fake the look of the horns in a pinch (in front of Jing Yuan, for example). Then before his exile, his horns are broken, to force him to hide them—one is irreparably so. (And yes. The fact that it is the same side that Taoran coincidentally has a single horn on was a design choice. :3)

Since Dan Heng can freely transmute his body, he can hide the evidence, and all the trauma successfully leads to this result. (Which, by the way, I love this idiot casually dropping that he was born with the "shapeshifting." Sir people will kill for unlimited dragon transmutation. They tried, in fact. Also if Dan Feng could just subtly change "his" face on his own he would have had at least 40% less trauma, but I digress.)

As for more fun biology headcanons, I think his tail *can* regenerate like many lizards, albeit slowly. Even more slowly when he's not getting those extra nutrients which I firmly believe he did not until literally joining the Express. His horns I think would be fun to merge the antler aesthetic of the dragon-avatar and also just the extended idle-animation horns he has with the fact that they are called horns, and model them after prong-horns, which means that the bone base is a true horn but it grows a "sheath" that extends like antlers and is periodically shed. Which. Incidentally. Makes them convenient for harvesting... (Because I am also a proponent of the idea that the "dragonhorn pillory" is a literal name.)

That said, when he transforms in the most dramatic and desperate series of biology-hacking in the Luofu quest, in lieu of his OG horn(s) and still half-grown tail, the residual cloudhymn that is said to be from Imbibitor Lunae kicked in and filled in with cloudhymn the classic IL horns, but since they are cloudhymn that's why they are transparent, though still solid and stuff. I have more thoughts about that form in particular but that's also worthy of a different post. I already know I am rambling.

Then as much as I love angst, I swear I like fluff too, so after Amphoreus, when he gets that extra Permanence power from Terravox (and then the heavily implied potential glance from Long afterward, because entering a daze and seeing an Aeon sounds like a very legitimate way an Aeon who might be living in the crack of the universe might show up), he can get a growth spurt and his second horn back, albeit gold because Amphoreus.

Also the scars. Hoyo always goes light on the scars but I don't lol. After that light cone, and the vague implications of the "undestroyed letter" dropped by Dan Shu, I am not convinced that a lot of abuse didn't happen down there (aside from the base abuse of locking a child up in mega jail), and the poor conditions down there will definitely mean they heal bad. And then Blade related injuries. Since he did get injured for sure in Blade's character stories. For evil Shackling Prison reasons most of them are on his arms and back though. (The fact that Dan Heng defends his bed because of back reasons too... And truthfully a good futon will be legit for this in some cases. This is another aside, but I know he starts sleeping in the Archives because of trauma reasons but I do think it's telling that a few times in story he does strongly defend staying in the Archives, despite him now having no intention of leaving. That's his comfy spot lol.)

The bad scar on his arm is through a few years of prototype pillories, often not size-altered soon enough. It is also the reason why the inherited bracer was changed from left-handed (how Dan Feng wore it) to right-handed. And then the scattered small marks are from removed scales that didn't grow back.