Feel free to adapt these names as you please.
1. Human names tend to have -ion suffix (Tyrion, Turalyon, Vairian), or a harsh sounding -Ar in their names (Lothar, Khadgar, Arthas).
My suggestion - Cillian, Irish for 'little church'
2. Blademasters tend to use Japanese inspired names. Lots are from famous samurai names or pop culture samurai movies/games.
My suggestion - Rashamon, after the Kurosawa movie
Or Ikiru, another Kurosawa movie, meaning ''to live'
3. There arent many famous Warlocks aside from Guldan and Teron Gorefiend. I say make something evil sounding.
My suggestion - Kraven, based on the word Craven meaning cowardly or defeated.
4. I translated eater of worlds in latin and it wasnt so cool. However, ''devourer of worlds" is pretty slick - Devoratrix Mundos.
My suggestion - Voraxx the Devourer
5. Demon names or names of powerful people could work.
My suggestion - Valcrist. Was the name of a guildy who was an aggressive raider.