This is my first time playing through Morrowind, but I have played Oblivion before.
In the quest Antabolis Informant, I met a bandit (Snowy Granius) on a bridge. He is a battlemage, can summon a skeleton, and can cast spells.
I tried to kill him with my Khajiit acrobat, and I couldn't hit him.
Then I made a Nord warrior, ignored the skeleton he summoned, and started to slash him repeatedly. Although I did damage to him, I still died before him.
Why is it so hard to kill him? I didn't try to level up because I think I can ignore the advice from Caius Cosades, who said I might need to do some quest from a guild.