Worked as a member of the ShinRa Works (later the ShinRa Company) Turks. He was sent to the ShinRa Manor to act as a guard for the researchers and there he met Lucrecia.

After growing close to Lucrecia he proposed to her, but she rejected him.

Hojo attacked him and experiments on his body, eventually leaving him on the brink of death, and Lucrecia revived him by embedding Chaos inside of him. Thinking that the transformation of his flesh was his punishment, he went to sleep inside a coffin in the ShinRa Mansion basement.

He reunited with his former colleague Verdot. A Support Materia for the Zirconaide summon was hidden inside the ShinRa Mansion and he knew about it.

When Cloud and company visit the ShinRa Manor and caught him up on the current affairs, he chose to join the group to meet up with Hojo and Sephiroth.

He confronted his fated opponent, Hojo, on the Mako Cannon. He angrily issued a death threat to Hojo.

After defeating Sephiroth in the Northern Cave with Cloud and the others, he and Yuffie worked together to evacuate people during Meteorfall. During this, although he thought he caught a flicker of life in Hojo, he lost sight of him.

He protected Cloud from Kadaj and his brothers when their fight got tough. He passed on the information about the connection between the trio and Geostigma on to Cloud.

He traveled with his former companions on the Sierra, rushing to Cloud's aid.

On his way to rendezvous with Reeve, he helped to stop a DG SOLDIER attack on the Revival Festival. Hereafter, he worked with the WRO and stood at the center of the fight with DG.

He learned about his connection to Chaos and Omega during his investigation of the ShinRa Mansion. When Rosso drew the Ancient Materia (i.e. Protomateria) from his body, he was gravely wounded and Yuffie rescued him.

He participated in the general offense to eliminate DG. When the ultimate lifeform Omega arose from Weiss' body he defeated it, and Chaos was freed from his own body to return to the cosmos.