Fūma is the younger brother of Seishirō, their familial bond evident in their interactions. He works as a treasure hunter for Yūko Ichihara, retrieving artifacts across dimensions. This dimensional travel was granted by Yūko in exchange for specific items, including a special jar hiding one of Sakura's memory feathers and a compass loaned to Sakura.

Arriving in the acid-ravaged world of Acid Tokyo four years before the main group, Fūma safeguards one of Sakura's feathers inside a magically shielded jar undetectable even by Mokona. He leads the Tower faction, refugees sheltering in Tokyo Tower, one of the last standing structures. His group frequently clashes with Kamui's Government Building faction over scarce water.

When the Tower's water supply dwindles, Fūma orchestrates an alliance. He offers the hidden feather to Kamui as a gesture of cooperation after the Government Building's original protective barriers, maintained by two other feathers, vanish following Sakura retrieving one from an underground reservoir. This allows both groups to unite within the Government Building, with Fūma's feather becoming a permanent safeguard for the water and the merged communities.

His activities span worlds. In Nihon Country, he delivers a prosthetic robotic arm to Kurogane, a transaction arranged by Yūko and paid for with Fai's magic and Princess Tomoyo's dreamseeing. There, he witnesses the confrontation between Seishirō and Syaoran, later teasing his brother about it.

Fūma displays a mischievous and observant nature, particularly with Seishirō and during negotiations. As a dimensional traveler and agent for Yūko, he appears across multiple worlds, motivated by fulfilling his contracts and ensuring the survival of those he protects in Tokyo.