Description
This alternate design I imagine would be a part of a darker history of her life as a mercenary in battle, the black oni mask kind of embodying her submitting to her darker nature as an oni and a killer of men.
So much so that when she eventually does move on I feel a persona would be etched onto the mask itself and cause a split in her personality whenever she wears it.
Cool stuff if I wanna eventually write her story for real.
An immortal's life is an unending journey full of struggle, this one was definitely inspired by Samurai Jack's arc in the final season's start being his fight with his inner demons having been stuck in the future unaging and thinking only of survival and almost succumbing to despair.
I think Sera would go through a similar stage in her life.