How it works at the moment:
- Fairly long summoning cast animation
- Fairly long animation of blight fiend rising from the ground
- A moment of him doing nothing
- (optional) Fairly long animation of casting Rotting Fumes, at times he glitched and tried to cast it more than one time
- Finally starts doing stuff
- Dies
By itself those things are not a big deal, but combined together it’s a problem. His actual period of activity is even less than stated 8 seconds.