Disclaimer: I don't own The World Ends With You
It would be surprising. It should be surprising. But it isn't when you put a little logic behind it.
In order to become a Reaper, one must be able to manipulate Soul well. In order to manipulate Soul, one needs imagination. Support and other low-ranking Reapers only have enough imagination to create walls or low-level noise, and that's all they need.
Higher-level Reapers, such as Harriers, need to be able to create formidable noise in order to properly hassle and erase Players. Hence, they have borderline overactive imaginations that make them appear rather eccentric.
The powerful imaginations of Uzuki Yashiro and Koki Kariya are what lead them to this logical, but perhaps unexpected pastime.
Laying on their backs, on the roof of the 104 building, picking out shapes in the clouds.
"Hey! That one looks like a frog Noise!"
Kariya tilted his head. "From this angle it's more of a woolie."
Yashiro scanned from side to side, then contorted her body to get a better angle. "That's almost a horse." She paused. "Is there any reason why there's not a pin for horse Noise?"
"Wolves have the whole running thing locked down, and frogs pack a nasty kick."
"Oh." Yashiro looked across the roof at her partner. "Kariya?"
"Your head's up there often enough. What's it like to be a cloud?"
Kariya quickly pulled his lollipop from his mouth so he could laugh without choking. "Maybe you should slow down and find out!"
"Mm. It's nice here."
Kariya rolled his head to look at her, and locked eyes over his glasses. "Dare I believe it? Did you just agree with me, Uzuki?"
"Maybe." She drawled. Kariya just smiled as they both looked back at the sky.
"Hey, that one looks like the Iron Maiden."
"Why am I not surprised it's a thunderhead?"
That had them both laughing… until someone cleared their throat.
"Excuse me, Harriers?"
The laughter was brought to an abrupt halt as they both looked over near the stairs. Mitsuni Konishi herself stood there, glowering, with the metaphorical storm cloud almost visible above her head.