Gai Tsutsugami is a major villain in the anime series Guilty Crown. He is one of the main protagonists of the first half of the series but in the second half he was revealed as one of the main antagonists along with Mana Ouma.
He voiced by Yuichi Nakamura in the Japanese version and Micah Solusod in the English version.
Gai was orphaned when his parents passed away and discovered by Shuichiro Keido used him as experiments along with boys for Apocalypse Virus which engagges Gai to escaped from facility and falling in the sea before he was discovered by Mana Ouma and her younger brother Shu who nursed him for his health and become best friends, Gai fall in love with Mana and Gai discovered that Mana was infected by Apocalypse virus which caused her insanity as Gai tried help her. But Mana was completely in control and blinded by the virus, she forced herself upon him, torturing him by tying him up and threatening him rather not to get in her way if he wanted to live.
Gai, nevertheless, intended to protect Shu and secretly called him to a church on the day of Christmas. On the same day, a family gathering was to be held in another Church where a young Haruka, who was fairly new to her stepchildren, had accompanied Mana and was waiting for Shu, Gai and her husband. Mana tricked her into going and looking for Kurosu as because of his workaholic tendencies. Mana went to the church where Shu was invited by Gai before he could reach, and cleverly tended Gai to shoot himself by aiming at a star on the top of Christmas tree which was made of such material that it backlashed the bullet shot by him.
As Gai wriggled and tried to survive, Mana stated that she used to love him, and immediately admitted that she was just lying, muddling her fingers into the pool of blood that formed beneath Gai. Mana used his dripping blood as her lipstick. However, by this point, Shu had arrived and he immediately succumbed to Gai's aid.
While Shu tried to help Gai, Mana summoned him to mate with her, to which he rejected as he saw her hair crystallize, perceiving her as a monster.
As Mana realized what she had become, she called to Shu for help, admitting that she was scared of herself too. But a young Shu could only back away in fear.
As Mana lost control over herself and triggered the virus to the fullest of her capabilities, Gai took Shu under cover and protected him. After it was over, Gai pushed over the rubble and promised to meet Shu again when he had become strong. He departed, but a young, shocked Shu took no notice of him, and eventually forgot everything.