If you are 1st place overall, your title is “Overseer of Gonzo”.
If you are not 1st place overall, but on one of the first three ranks of a challenge category, then you’ll get one of the following titles:
Prefix:
1st place: Master
2nd place: Expert
3rd place: Adept
Suffix:
Combat: Warrior
Crafting: Crafter
Construction: Constructor
Exploration: Explorer
Social: Diplomat
The highest rank decides. So if you are for example on rank 2 in exploration and on rank 3 in combat, you’ll get to be “Expert Explorer”. If the previous doesn’t apply and if you are on the same rank in more than one category, your title is decided by the aforementioned category order. So if you are on rank 3 in construction and on rank 3 in social, then you’ll get to be “Adept Constructor”.
With more features there will be more challenges in the future and probably more challenge categories as well.