Really? Just think he'd be a one off? Frankly I disagree.
Generally looking at Santa Claus you'll see he is a philanthropist, an entrepreneur, a man with a clerical bent, a gourmet, etc. These various traits which flesh him out as a character. And Santa has much to deal with, there is a whole multiverse that needs Christmas Cheer.
Sinterklaas is a rather important individual, who exists to help cultivate joy and revelry for all people to enjoy. Santa has to deal with both the past of how he did his good deeds, and how the ever-changing times makes the experience of making people happy around Christmas a joyful time.
The man is devoted to doing good and helping others, and not always just by delivering presents. Let us go back to one of his exploits from Saint Nicholas. He saved three children from being butchered into meat-pies, by praying to God and the kids were saved and kept alive. More modern versions of Santa have fought martians, demons and the Boogeyman even in order to keep the children and people of the world safe.
Throughout the years, he has had various changes to his appearance and depiction but there was always the constant that Santa was a good guy who wanted to make people happy. And that is his eternal quest, spreading joy, peace and love and of course Christmas Spirit, in a jovial and jolly manner. And with so many possibilities to do good, it won't end anytime soon.