I think this skill should be changed to a toggle ability just like how people can stay in werewolf form for a long time with an obvious downside being that when you enter this form you can't talk to any NPC aside from what you summon and you will have a hard time entering any zone that can put a bounty on you.
basically this makes it exactly like the vampire lord form as seen in elder scrolls V skyrim except you don't have wings and you don't hover.
one more thing to balance this. add a 30min maybe an hour cooldown before you can enter this form again.
I just find it very unfair that people have waited to get this ability to turn into a sorta vampire lord form but it lasts only 20 secs.
Guild master of Darkness of Sanguinaris. Birthday is December 4th.