The standard melee build that I recommend to any 2H or Polearm users is quite effective in a one v. many situation. Of course, it relies on the player having some competency in knowing what he or she is doing, and a good command of blocking and footwork. But nevertheless:
Level 30 (4 420 577 xp)
Strength: 24
Agility: 15
Hit points: 75
Skills to attributes: 8
Ironflesh: 8
Power Strike: 8
Shield: 2
Athletics: 5
Weapon Master: 0
<Either>
Two Handed: 111
Polearm: 111
0 WM because WM is completely unnecessary for melee combat, especially 2H/Polearms. 2 Shield helps protect your incredibly alluring body from archers, throwing, and weaker crossbows. And besides, your focus is not swinging your 2H or Polearm at the speed of light; it is to cause maximal damage with each swing. This point needs to be re-emphasized: the more damage you do with each swing, the higher likelihood you have of killing your enemies and suddenly turning a 3 on 1 into a more manageable 2 on 1, or a 2 on 1 into a definitely manageable 1 on 1.
This is not to say that 1H shielders are not designed for one vs many situations; in fact, they're at their strongest when they can attract multiple enemies at once, because that means that the enemy team is committing more to taking out just a single person (you). I would still recommend a Strength build, however, perhaps along the order of something like this:
Level 30 (4 420 577 xp)
Strength: 24
Agility: 15
Hit points: 69
Skills to attributes: 8
Ironflesh: 5
Power Strike: 8
Shield: 5
Athletics: 5
Weapon Master: 0
One Handed: 111
Your shield will help absorb multiple attacks that would otherwise be unblockable, and it is up to you to seize each breathing moment to slice at an enemy's face and hopefully take them out. Your shield will not last forever, especially against axes, so in my opinion it is better to maximize the damage you can do with each strike.
