I'm extremely sorry if this has been asked elsewhere, i searched and coulding find an answer. How exactly is vampirism handled between morrowind and oblivion? like if i contract vampirism in oblivion will i be in a clan in morrowind? and do oblivion vampire mods work?. also wondering exactly how werewolves work and if i can be a werewolf and a vampire at the same time (i haven't played oblivion in years and i'm extremely new to morrowind)
Thanks in advance for the patience and answers, sorry to be troublesome. keep up the good work guys

You contract Vampirism from fighting Vampires. The Clan you will be in depends on the Vampire who infected you. It works pretty much the same as it did in Morrowind. The same goes for werewolves. You can become one during the course of the Bloodmoon main quest and yes, you can be a Vampire and Werewolf at the same time.
thank you for the info, if i were to contract vampirism from the dark brotherhood questline in oblivion, do you know what clan that would put me in?
I think Morrowind's and Oblivion's vampire system work independently from each other. So you can contract both diseases. However if you're cured of Vampirism in Cyrodiil you can't contract it in Morrowind.
ok thank you so much!