Can I kill Kerghan without the Vendigroth Device?

I (naively?) gave it to K'na Hua before going to the Void. If not, is there a way to get out of the Void, get it, and then go back in to finish him?

 

If you look here you will find the answer to your question.

 

My guess would be yes, but I dunno for sure

 

You can for sure, the first time I finish it, I got the device but forgot to use it coz Im busy whacking him with the sword from the void, best weapon in the game.......

 

He's definitely killable without the Vendigroth device. I put on a Dweomer Shield (the one that makes you immune to magic) and killed him while he was in his recovery cocoon.