Defeating a Ghost

I'm trying to complete a quest in South Midmaer way. I managed to open a crypt which is home to a ghost that cons yellow to me. I got him down to around 25% but it started to siphon me and I eventually ran out of focus.

my adventure level is only 44, im a caster mostly. my prefered weapon is a 1h blunt and a wand in the offhand. My main schools of magic are Death and Fire.
Im curious if its worth learning Banish Undead under the life tree for ghosts and other undead?

are there any tips for avoiding the life drain without going too far into another combat school im not focusing on?

 

you can cast purify and celestial blessing to boost your death resist to weaken the syphon power of the ghost

 

thanks! ill give it a go tomorrow.