The Clowns (ピエロ, piero, from French pierrot) is a small group of Ghouls with no known goal or purpose. Its members primarily wear Clown-themed masks, and state their intention to "have the last laugh". The CCG has planned a famous investigation on them in the third ward, as mentioned by Hide, but their current residing ward is unspecified.
The group is mentioned throughout the series, but revealed at the finale to have been involved in numerous pivotal events.
The Clown group has had a long history well known in the public as CCG spend quite sometimes on their investigation and eradication plan. Kishou Arima, Take Hirako, and Kousuke Houji are CCG members that are involved in the battle against them.
Yamori had some unspecified history with the group, leading to his confinement and torture by CCG.
Throughout the course of the series, the group have been involved in critical events either as individuals or working as a group.
The group reappears during the Auction, serving as entertainers and Auctioneers.
The group have been involved in numerous key events through the series, either as individuals or working in conjunction with other members.
- The Steel Beam Incident. (Souta)
- Kaneki at the Ghoul Restaurant. (Itori)
- Kaneki's capture by Aogiri and torture by Yamori. (Nico)
- Search for Kanou's Lab. (Itori and Nico)
- The Auction. (Uta, Roma, unnamed member.)
- Yamori mentions that the Clowns group was rising in power during in his time in Cochlea.
- On the Cochlea ghoul escapee list Kaneki gave Itori, there is a SS rated Clown. Of the three SS escapees, one is shown to be a brown-haired woman -- suggesting that this is Roma. 
- All major Ghoul organizations within the series had at least one Clown either associating with or joining them. Uta, Itori, and Roma were all associated with Anteiku. Nico associated with Aogiri for a time, while Souta was a member of the Gourmet Restaurant in the 7th Ward. The Clowns are also involved in Big Madam's Auction.
- "No point in living if things aren't interesting. The ones who get the last laugh are us, the Clowns."