Costume Kingdom

This Quest will become available once you’ve completed the first Apex (see The journey begin's). You need to talk with Bill to pick it up. He's located on the bottom right corner of the town, just next to a dirt pathway leading right:

He'll task you with finding Julius in the forest, which is just beyond that dirt path just to his (Bill's) right. You'll actually make progress towards Marcus the maniac as you go for this one, as that one requires you to defeat Marcus' goons, the majority of which are on the way to Julius. Make your way along the dirt path and go through all the battles as they come up (they'll start automatically). Just about halfway through, you'll meet Julius in the middle of the pathway (he's a white-furred Monkey, near impossible to miss). When you make contact with him, he'll disappear. Note that a second Julius is also visible in the forest but is unrelated to this particular quest/trophy.

Once you've interacted with the first Julius, head back to Bill to turn the trophy in. When you do, the trophy will unlock.