Vampirism mod effect (help with making a vampirism effect for vampire player, that can work on multiplayer)

Hi, i am making a vampire mod and i am trying to make a vampirism effect that makes u turn into a vampire when it ends (or if possible when u die before the effect ends) and then u get vampire powers like strength speed jump boost etc. and maybe when ur a high enough level, u could turn into a bat or something, but i need help creating the vampirism effect and the vampire powers, so plz plz plz help me plz, i have looked on other forum discussions but they r not quite what i need.

P.S I am still new to mcreator, i have only been using mcreator for about a month now, so if possible plz use pictures maybe.