DeathSpank: Thongs Of Virtue

Story related. Santa is a plot antagonist located in the North Pole. To get there, you need to fulfil the requests from the Army General in Beaux Kuckelle. The requests are:

1. Map out the North Pole
2. Obtain a Chunk of Gold
3. Obtain Gun Parts

Glitch Note: Before you proceed to the North Pole, I would advise you to backup your save file as there is a known glitch with Rudolph the Reindeer (Credits to Breadskin). The Reindeer is supposed to appear and drop an equippable item that must be used to defeat Santa Claus. There have been reports of Rudolph not appearing. See below for a potential solution, or reload your save file if it happens. Ultimately if both methods fail, you'll need to replay the game again.

Potential Glitch Solution provided by theone. Also more info HERE
I got that same glitch and tried everything beforehand:

Then I just let my lv21 Deathspank get killed by the reindeer's for the heck of it and that actually solved the problem for me as once re-spawned, the red-nose bastard was just standing there >.<


Walkthrough
To Map Out the North Pole, you must first have completed the "Raise Your Mast" trophy and gain access to the Pirate Ship. See the trophy for info on that.

Once you have ship, travel in a circle around the North Pole and you'll see Buoys. Hit 10 of them and you'll complete this objective.

The Chunk of Gold can be obtained from Madama Primp in Strumfuguel. Again, I must stress that you should have completed the trophy "PRIMP V.I.P" before attempting this step as it is missable. Engage the services of Primp one last time, and while she is changing, quickly open the Odd-Looking Chest beside the bed.

The Gun Parts are obtained in the Sanctuary if you were thorough and followed my walkthrough for "Death of a Penguin". When you enter the catacombs, take the lower path and you'll come across a colour puzzle, which isn't really difficult. If you're still struggling, remember to use Fortune Cookies to unlocks hints and the puzzle solution.

When you have all these, return to the Army General and he'll transport you to the North Pole. Go down the left path and you'll reach Santa. He will use some trick and throw you into a very short dungeon that only takes a few minutes to traverse. The exit of the dungeon is opened by operating a series of levers labelled 1, 2 and 3. They move the bridge by a number of steps corresponding to their labels. You just need to match the bridge to the exit (the path with lights/not caged).

Upon exiting, head North and you'll encounter Reindeer, a Mini-Boss. Please remember to backup your save file prior to this. Defeat him and obtain his Antlers. There is a potential glitch which may occur here as mentioned in the Note above, where the antlers go missing. Equip them if you have it, then teleport to the Outhouse nearest to Santa. Go up to him again and watch his trick fail. He summons a minion which should be very easy if you have ice weapons/grenades/bazookas and took me only a few seconds to be defeat. The trophy unlocks after this