Olaf is the tritagonist of Disney's Frozen franchise. He is a benevolent, wisecracking snowman that was enchanted with life by Elsa. Along with the ability to reassemble his body, his most prominent quirk is his love for summer and all things hot.
Vote which fictional character would naturally fit in-universe with a big-named franchise! No time-travel, no interdimensional crap, no "Pooh's Adventures", they would just exist in-universe.