When he first appears, Trinita is covered in blood and so the characters are unable to tell his color. When it appears later, Trinita is described as a male white cat with a pretty face and short fur. The cat had a black cloth collar with a silver heart-shaped nameplate hanging from it, along with a phone number and the owner's name written. Trinita had spend his days with Hanae and held an affection towards her.
Trinita was a cat who, alongside his mother, belonged to Hanae Orikasa.
Trinita was Hanae Orikasa's cat. She saw her master talking with a "student with red marks on his arms" moments before her death and escaped to the street, but was soaked in blood. Trinita was eventually found in a bloody state by Rohan Kishibe and Koichi Hirose, who found Hanae's body after looking for Trinita's master. Trinita was kept at the police station during the investigation, but was retrieved from there by Koichi so Rohan could use Heaven's Door on the cat and find clues about who was the killer. Koichi then took Trinita back at the police station.