aatrox and rhaast look demon like with very prominant red and dark colors. Varus on the other hand, if we are going by the music video, looks VERY human with white and purple colors. If he hates humans so much why does he look so human? and im not talking about the body he took after the fusion, im talking about what he looked like during and before his imprisonment.
Cause they retconned a not Darkin to be a Darkin.
They can add as much dressing as they want over it, that is still the reason.
Because half-assed retcons lead to continuity problems.
My theory is that Darkin appear obsidian only after they completely seal away the consciousness of the original host. In Varus' case the Darkin is still fighting over control with the two merged hosts.
Why do Darkin take an obsidian form? Well I can only guess the Darkin use some kind of blood magic to transform the human body (or their host) to a more resilient version. That would explain why Varus' "spirit" looks so different from the typical looks of a Darkin. Maybe Darkin are originally more humane than we think.
A rioter once said something about this, I'll edit this when I find the link, but apparently when they possess human bodies, they kinda rot over the years. and that what we see is how the body holds up over that time. note how the body slowly corrupts in Kayn's case, but only the arm, and the in game depction of rhaast is a full takeover at a time we don't know yet. It could 100 years past a takeover. Varus's body was a created form, so I think it's actually closer to the Darkin's true form than Aatrox or Rhaast.
Because Varus fused the flesh of himself and the two Ionian hunters Val and Kai. As far as before his transformation goes I think that’s the closest to the true darkin we’re getting.
read what i said, im talking BEFORE he fused with val and kai.
Well we only see the legs and hands of the darkin
I think that no one has answered the question yet... the OP is not talking about 
, he is talking about:
https://i.imgur.com/TwrC3zY.png
I guess that that is the original form of the Darkin race, and what we see in game is the shape that the Darkins take when they corrupt a human.
Darkin better not resemble humans,that would be a shitty cheap cop out.
But this has bugged me too.
The vibe I got from the video is that that form is loosely based on Kai. It's not necessarily what the Darkin look like, but in lieu of a physical body he made a crude phantom to use as a temporary avatar. Notice how the lights come into Kai's body and then the spectral form appears from within him.
Because he was (probably) created via Void corruption originally.
Purple/black is their thing.
Then he got ret-con'd with no visual update.
i think i has something to do with the one guy (i cant remember the names from the stories) making a deal to save the other guy in kayns story rhaast will fully corrupt kayn taking control of his body and making it look more demonic where as in the varus comic you watch the darkin and the two guys "fuse" into one being when rhaast takes over there is no sign of kayn left but in varus' story it seems like they are all fighting for control of the body in the mind but im not 100% sure this is just my take on things based on what we were given
Because he used his new gayness to make himself look fabulous instead of ugly. [zombie-brand-clap]
Maybe there are different subraces of darkin?
Aatrox and Rhaast are red darkin,who are the demonic looking frontline fighters Varus and his sister would be purple darkin who look more humanlike.
because he has a rainbow stuck up his arse.
"A great many of the Darkin were humanoid in appearance (though not all...) and the forms they have in Runeterra, are the best approximations of their original forms they can craft with the crude matter of mortal flesh as a canvas. The bodies of their hosts degrade over time as the weak, human flesh rebels against this transformation and new ones must be found. I imagine Varus's original form to be so stunningly incredible that it would hurt to look upon him, and that, yeah, you might very well see the ideal form of what you desire reflected back at you."
This is directly from dinopawz
