Yuki, half sister to Bara, and a experimentalist at heart. Yuki is a scientist who works at Love Labs, which is ran by none other than The Green Twins.
Yuki Blight, Love Lab's best scientist, and older half-sister of Bara.
I'll just say it now, yes, I watched Kimetsu no Yaiba, that's where I got the idea for the eyes from. Besides that, she's completely original.