Yeah, but you'd think Dante would be like "wait, why didn't Demis tell me everyone had to do this today" considering Demis also fucking works there lol
It's especially sus seeing as Demis would have warned Dante and come up with a way to avoid potentially exposing Dante's secret. Instead, he was like eh sure whatever fuck it. He has completely thrown caution to the wind despite the fact he's still being hunted.
I mean, not busy enough to literally rearrange Dante's guts almost every time he sees him lol
They also live together, and Dante's safety, especially after the priest situation and the cop sniffing around, is Demis's number one priority.
Like I said, it just seems a lil slow of Dante to not even question as to why Demis didn't mention a hospital wide blood test. You'd also think Demis would be the one to take his blood if absolutely necessary so he could fudge the records or something.
It's a plot hole for the convenience of creating yet another conflict for the two.
LOLOL
He's become too lax, and I get that he's excited that after decades of not being able to die there are finally signs of his immortality waning. It's just kinda ooc for him to suddenly not give a shit about potentially outing himself when the church that is after him is clearly still very much active.

OMG!!! I feel like the MC is so slow!!! Why would he allow someone draw that much blood and not ask any question at all. Or am I just think about it too much?