Thanks for the offer, Kivuli, but turning Rydar into a vampire - at least for this RP - will add an interesting layer to the mix. As well as a sort of side-quest that happens along the way, where Rydar tries to cure himself.
Plus, weasling out wouldn't really make sense because Kaz has already shown quite the interest and - I assume, because he is your character - probably wouldn't let it slide.
Also turning Rydar into a vampire would give him more reason to follow Kivuli because he is now a part of the main story. Instead of an Argonian who just happened to be in the wrong place at the wrong time.
I've thought a lot about it and while being a vampire is going to be hard on Rydar - but great for the RP - it adds too much to simply brush away.
I say go ahead, let's make Rydar a vampire.
(I'm really glad I played the Dawnguard DLC. With an Argonian, no less!)