This is my first play through of this game. So far I am in the drowned nation. I have myself, Dak'kon and Morte.

I am just walking around where there are Varangians or whatever those flying birds are called, and Dak'kon keeps running out of health. Morte and myself are fine, no real problem unless we get swarmed but Dak'kon will start running low on health if there are 4 enemies around.

Is he really so weak or am I glitched?

He does absolutely insane damage after he levels up a few times (to get the first sword upgrade) but he never has great health. His AC is mediocre unless you give him one of the mage armor rings, too. Really though, you shouldn't be using him like a straight fighter. He's a mage as well, and has access to a variety of useful spells to either kill enemies at range or to protect himself. He's actually one of the strongest characters, but he can't go toe-to-toe unassisted.

The character you should be using to take hits from monsters is Morte. His AC isn't that great, but he has huge damage resistance and can taunt foes into attacking him. Once they've focused their attention on Morte, use Dak'kon to kill them. Morte also has the advantage of being a valid target for embalming fluid and embalming spells, which heal him and improve his AC.