You never wanted Eridan to find out like this, but you actually never wanted him to find out at all. "So all this damn time you'we just been hidin' the fact that you're a filthy, dirty wampire since w-we've been talkin' to each other!?" Boy did he sound more than pissed, enraged even. You knew he would be pissed, you two were close and he just found out one of his best friends (you aren't assuming, he has told you you're one of his best friends) is a vampire, something he despises and is supposed to kill.
You just giggled lightly. "Mhmm, I am. I never told you becauthe I fucking knew who you were and I knew you would kill me if you got the chanthe to when we firtht thtarted talking to each other." It was really that simple, actually.
Eridan looked torn. You knew he didn't have many friends from your late-night discussions and he never wanted to lose you because you were one of his best friends, one of his few friends, and he would make sure you were okay before he knew about your little toothy secret. Now, you're not so sure he is willing to keep you safe anymore or just turn around and do the exact opposite, slaughter you. All he seems to do is sigh. "W-why the fuck did this hawe to happen to me..." Trailing off, he looked around the area to see if there was anyone, and you almost ran away, fuck, you should have run away with how he was looking around, but you didn't.
That was highly stupid of you, because even though he was, and you still like to think is, your friend, he is supposed to kill creatures like you, and you're not so sure if he wants to continue with what he should do because of his job, or forget all about that and let you off the hook.
When you feel a needle in your shoulder, you realize you waited too long to think as the world around you spun as you fell to the ground, blacking out, hearing the heavy footsteps of Eridan approach you.