The Washuu clan (和修家, Washū-ke) are the central family who leads the CCG, having been involved in its formation. Its members have hunted ghouls for well over a century, exterminating them using specialized methods. In 1890, the Japanese government enlisted the family in the founding of the Counter Ghoul Institution (喰種対策院, Gūru Taisaku in), a federal government agency that would manage and pursue ghouls. Since then, its members have acted as prominent officials within the law enforcement agency.
It is noted that Washuu members are known for being serious investigators who are concerned about results and are hard to get along with as they are willing to sacrifice many people to complete their missions, perceiving them only as numbers. The only known exception is Yoshitoki Washuu, who is notable for being hospitable and benevolent to his subordinates.
Eto Yoshimura later claims the Washuu clan has a long-standing alliance with the ghoul organization V. She further alleges that the clan was involved in a conflict with a powerful one-eyed ghoul and this conflict resulted in the formation of the CCG.
Ironically, the Washuu clan is actually comprised of ghouls posing as humans. Using their authority, they have kept their true nature secret since the formation of the anti-ghoul law enforcement agency they administrate. Itsuki Marude discovered their secret through a personal investigation of the family's members. He explains that he found absolutely nothing suspicious except for one minor detail: when he examined the records for the Rc Scan Gates, he noted they registered a false positive whenever a Washuu walked through them.
The Washuu clan includes numerous branch families, tasked with carrying out different duties. These groups include the main family line, responsible for leading the CCG and being the public face of the larger clan. In secret, they also assign individuals to specific roles within a breeding program meant to preserve the pure-blooded lineage or to produce half-human agents to serve them. These individuals are known as "Seeds" and "Wombs," responsible for siring or bearing offspring to further the clan's agendas. According to Souta Washuu-Furuta, these breeding programs involve incestuous and non-consensual relations between the primary Washuu bloodline and "Wombs."
- Daikichi Washuu † - CCG Founder
- Yoshiu Washuu † - Previous Chairman
- Tsuneyoshi Washuu † - Chairman
- Yoshitoki Washuu † - Bureau Director
- Matsuri Washuu - Division II Commander, Special Class Ghoul Investigator (Missing)
- Iyo Washuu
- Kichimura Washuu (Nimura Furuta) - Rank 1 Investigator
- Kichimura Washuu's mother - Womb 
- Rize Kamishiro - Womb 
- Rize Kamishiro's mother - Womb 
- Half-human agents from the Sunlit Garden
- Kishou Arima † - Special Class Investigator
- Yusa Arima - Ghoul Investigator
- Kishou Arima's mother - Womb 
- Rikai Souzu - Ghoul Investigator
- Members of the Washuu Clan add '吉' to their given names, meaning "good luck."