Graham

Graham is the first "partner" Tiara summons, appearing in episodes 5-6. However, he was disfigured during the process. Tiara had to fight for a long time to possess him, while also battling a demon formed from her own shadow, which is now the demon-like creature she can become in battle. Because of this, Graham initially feared Tiara, but his fear soon gives way to fierce loyalty.
Graham feels that Tiara's love for Kagetsu is unhealthy and views Kagetsu as the source of her pain, though most of these thoughts stem from his own affection for her. Graham attacks Kagetsu in the final episode when Kagetsu steals The Throne of Yord (which contains the soul of his sister Sara). Unable to match Graham's superior physical strength, or perhaps simply unwilling to use force against Tiara's partner, Kagetsu "neutralizes" Graham during the struggle. Since Graham's physical form was sustained as an extension of Tiara's magic, having her magic neutralized eradicates Graham's body.