1. Cleric
Most useful character with DOTG, HOP, and DOP. Helps increase melee damage and defense. Try to get Light magic to 60 by end game or 40 with an item of light magic.
2. Dark Elf
Has almost all of the useful utility skills. Also can master swords or knife and the best bow user. Can master the elemental magics. Getting GM in these magics is a real pain in this game.
3. Vampire
Can GM dagger which late in the game is the third most damaging melee attacker behind Knight and Troll. Also early in the game will attack much faster than other characters. Also has some useful skills. Can expert item and disarm trap which is more than enough if you can find items of id item and disarm trap. Can master the 3 schools of cleric magic. Can serve as primary or back up healer depending on party with shared life. Can save skill points for the cleric if they master spirit or body so the cleric can concentrate on light magic. Also has levitate which is useful in a few spots as well as for avoiding most of the traps in the game.
4. Lich
Most damaging character and has some useful skills. Only drawback they die very easy for the first 1/3 to 1/2 of the game. Lloyds Beacon is useful but getting GM water is a pain in this game and I don't like abusing invisibility.
5. Knight
Other than melee only useful for repair item and maybe expert disarm trap.
6. Dragon
Can GM id item and perception and the later isn't too important. makes the game too easy
7. Troll
Can repair gear if no knight in the party or have the knight save on skill points. Can duel wield sword and mace. Terminus works best and you can get two of them once the area respawns. Mace is bugged so adding skill points doesn't increase damage.
8. Minotaur
Axe is bugged with reduce recovery time not working unless that's been fixed with the patch? Could use spear but if using spear might as well use a Knight. Only useful utility skill is master disarm trap and GM perception. Can expert leather, or master chain or master plate.