Mordekaiser alt utility buff?

What I was thinking was the ability for Mordekaiser to get more enslaved souls (refereed to as ghosts from now on). So my idea for a new version of his alt time is 35/50/65 but when you curse a champion/dragon and kill it your Ultimate comes back for 10 seconds to curse another person so on and so forth until there is no one left to kill or the 10 seconds run out. As you kill people the timer for your previous ghosts resets as well. (When the 10 seconds is going for you to curse someone else your ghosts do not degrade). This may be considered OP because if Mordekaiser gets a pentakill its a 11 v 5 (including dragon here) and its pretty much game over if you are within spawn radius for like 45-75 seconds depending on leveling. I have an idea to fix that as you get more ghosts the stats of each decreases. 1 Ghost regular health, 2 Ghosts 2/3 of regular health, 3 ghosts 3/4 regular health, 4 ghosts 2/4 regular health, 5 ghosts 1/4 regular health, 6 ghosts 1/5 regular health, 7 ghosts 1/6 regular health. (The Dragon if ghosted counts as two to balance it more if there is no other ghosts the dragon counts as 1, and if lowered health on the ghosts isn't enough to balance it reduce overall stats) (If no in the poll please comment why you think so)