I just finished the vampire QL and I'm doing the side quests that the vampires give you and i realised there repeating themselves just with different people. I was wondering if they run out and if there any really good reward through doing them

To be honest, I don't think so. Same goes if you Join DG.

Im sure its just like the Companions jobs after you finish that questline.

I don't know where to ask, so I will use this topic.

To start Dawnguard questline you have to start vanilla MQ ? I'm asking becouse if not the dragon in Soul Cairn can be your first slained dragon, and the related to him shouts be yur first learned shouts.

You don't actually properly kill the dragon in the soul cairn so no I don't think so

you get rune weapons if you do alot of missions for the dawnguard. you have to do all the crossbow quests,then 2 from gunmar, then 1 from isran, then 2 from feleticus(i think that is his name) adn you get the rune hammer. repeat this proccess to get the rune sheild. and im currently working on getting the rune war axe. dont know what happens after that.

I just got a quest to kill Dawnguard leaders so I think it may actually progress

The quests given by the factions are not radiant per say, as in the appear to escalate in difficulty and lasting impact, so you actually make some progress as opposed to just farming gold as with the companions

No you do not have to start the main quest, and no you really can't kill him as he is not really alive anymore. He will teach you the shout, but he nor you understand why you can talk to each other and if you continue to talk to him after he gives you a dragon sort of nickname, your character will say something about not being a dragon and he will say he felt the need to give it to you. He also talked about the possibly of finding out why he felt that, indicating the MQ.

Thanks

No problem.