Oh my. What in the world. Let me help a bit. Most if not all of the names in greek dont really have a translation into any of the words you wrote, so let me rewrite the ones I think would be best written in greek:
Deathwing - Ντέθγουινγκ
Imperius - Ιμπέριους
Leoric - Λεόρικ
Ragnaros - Ράγκναρος
Rexxar - Ρέξαρ
Thrall - Θράλ
Yrel - Γιρελ
Again most of these words dont actually mean anything in greek im quite sure.