Final Strike on a hard difficulty setting requires full heath, on a low setting not much. What I'm really saying is most of the events talked about here have been tested on easy machines and hard machines, but again you may require something special in order to get it to work. A cleric is almost a certantity in any party. These guy heals you up and can get rid of those pesky undead. Mage has great boss killing potential.
Fighter is the guy who can use any sword is the level clearing guy.
Dwarf is like the fighter, only slower but more powerful. Thief can also use any weapon, but doesn't have as much health, and can't block. Although thief can open any chest. She can use any sword, and cast spells. Disadvantage, swing is slower and has a lot less health.