[Warhammer]

High hit points and number of opponents, is much less a concern than high AC and high resistance IMHO.

Anyway one must adapt to the enemy. If he uses ranged attack, get up missle shiled. If he is a firebreather get up element shield. If he has low mental defense turn him insane. If he only has melee attack engage him from afar. If he has high AC, armormelt him... and so on...

The other thing to do is getting your characters good weapons, equipping your lord with Bloodlust and your fighter with Fang doubles their effectiveness, at least.

Using the environment can also make things easier: Fighting in doorways, corridors or with your back to a house or a cliff can avoid a lot of trouble.

Finally, the game being non linear you can end up in places where the mobs are simply too strong, so if everything else fails go back to other areas you know well to gain a couple of levels, before giving it another try.

Hope it helps, if not try posting your party composition and the area/opponents you are having trouble with, we might be able to give you more specific help.