>>78932545Design-wise, it's because unlike all other recurring female character designs, Canyon's design has actual fully-drawn eyes, a mouth with basic detail, and a body with decent anatomy that doesn't tend to melt into noodle-armed chaos.
This blows the typical button-eyed, spoon-faced, low-detail, noodly female characters' designs out of the water, even the water nymphs are the premiere background character fapbait. Everyone is a flat, noodly mess with a barely-existent face that requires significant amounts of artistic license to make attractive, whereas Canyon looks like a woman in all respects and all you need to add for fapping pleasure is tits/ass/etc. naturally missing from most kids' show designs.
Plus, character-wise she's one of the few female characters that hasn't treated Finn like shit at any point so far in one form or another. And, as
>>78932789 said, she doesn't have a 2deep4u Mary Sue characterization and backstory. She's just a giant elf-looking chick who hung out with a legendary hero she was pals with up until he died, then started spending time with his biggest fan and closest thing to a protege afterwards.
