You saw the blood in the fridge. The thing with source-bloods is while they are born vampires their powers lay dormant until some dark event
![[Torobakoya] Class No InCha Ni Yorokonde Nikutai O Sashidasu Anoko](https://data.e-hentai.vip/uploads/157/1571027/poster.jpg "[Torobakoya] Class No InCha Ni Yorokonde Nikutai O Sashidasu Anoko")
You saw the blood in the fridge. The thing with source-bloods is while they are born vampires their powers lay dormant until some dark event