Lycanthropes
Werewolf
In nature - A shamanic and sparse race of large, bipedal beastmen living on the green peripheries of Sheol's first level. They are rarely seen or heard from by even demons, and are not recognized as natives to the land.
Double the human form's weight for Lycanthropy-afflicted humans.
Bipedal, innately well-built beastmen. Female Lycans are often slightly broader-limbed; storing slightly more fat than the males.
Skin is pinkish, but the fur color varies heavily based on individuals - however, the only silver-haired Lycan at any time is the Alpha.
6.5-8ft
They're fucking werewolves, for one.
Lycan form in Curse-born Lycanthropes has no genitalia.
No noteworthy variance save for the shape of some front teeth, it's hard to tell them apart otherwise - outside of scent.
For afflicted humans
Whatever they were wearing beforehand, though it'll probably rip...
Unalloyed, pure iron will penetrate their hides with at least relative ease.
Staying out of the moonlight for too long will wrack a afflicted human with pain and eventually force them to revert to their natural state.
Afflicted humans in their cursed form possess thrice the (normal) physical strength of the afflicted's human form. They boast a resistance to kyei-damaging effects, as well.
Their smell and hearing are enhanced threefold.
Trade-based
Sheolean wildlife, these days, though most if not all red meats on Earth are welcome
The strongest at any one time is often "elected" to lead society and hold the Mask.
Shamanic stuff here
By choice, simple stone age-tier
Using basic tools to "trim" patterns into the fur on the arms, chest and/or back
You'll have to ask a historian of their people if we encounter one
You cannot be a Lycan and a Vampire at the same time.
You cannot be a Lycan and a Midlord at the same time.
The transformation is painful, because your body is magically stretching and deforming but will not break.
Doing the first two things will cause your kyei to unravel and your body to fail and enter rotting almost instantly.