can ya'll share your theories on this??

I’m thinking he might have turned en into a vamp, from the flashbacks that en is starting to get.... maybe,...,

What we got so far

- ichii transformed the same way as en, its incidentally happen, cause ichii told en he had the same reaction as his back then
- it mentioned ichii had past pairing and also unknown-but-certainly-bad past
- ichii loves to help people so he join health fang department
- he had cross tattoo across his arm the same as tan-skinned fang at ch 5 behind his neck

so to connect all that, I had this theory;

in the past maybe ichii had a lover that bitten dry by other fang (perhaps a high ranking one, as mentioned they could erase the evidence and make it seems nothing happened) and that makes ichii goes rampage thus he banned from the pairing party for a while. then he started to help other fang as coping mechanism for himself to stay sane and prevent high end fang to mess more people. the one that mess up got this cross tattoo as symbolic way to remind them the dark past, or to remind them they used to be a human. i suspect the one responsibility for blood rampage in ch 1 is same person as tan skinned fang in ch 5

i'd like to hear others theory tho, how bout it?

I missed the cross on the killer vampire at the end. So we presume that the dark haired vampires kill other vampires at a pairing party. Maybe he is Ichii's pair and when he went crazy Ichii didn't manage to stop him (or report him on time) so that was why he was banned from those parties for some time. So his ex is at prison (or dead). I do not want ex mess. I prefer for it just to stay as emotional baggage and nothing more

I meant "dark skinned" not dark haired

well my theory on this one goes like this...

maybe Ichi got involved with the ancient vampires and went along their "killing spree" and the cross was some sort of physical evidence to show that they are in a pact not a pair. and theeen maybe to complete this "pact" ichi had to drink ancient vampires' blood, and despite leaving for so long, the scent of the latter still lingers because of how pureblooded their blood is. regarding the time he saved En, i feel like he saved him because he wanted to somewhat redeem himself for all his sins and that he reminds him of how he was before he turned into a vampire. and the reason why Ichi closely supervises En is so that he won't stray away from the right path unlike Ichi who made a mistake of becoming allies with the purebloods.