@Whatif Yo mate, just an observation, its Death Knight, not dark knight.
@Severius Unfortunately it's like @Gofur said, some class's need alot of investment ($$) to be worth, different of other class's. In general, support class's don't need too much of investment (iss/tank/healer) but on pve it's not too much useful. Yul archers are most expensive class, but are really good. Death Knights are not too expensive like archers, but still need one considerable level of investment. But between Feoh and Othells, without doubt, feohs are more cheaper to play.