Ventus

Ventus, also known as Ven, is one of the main protagonists in Kingdom Hearts Birth by Sleep. He was a Keyblade wielder before Sora ever became one, and was apprenticed to both Xehanort and Eraqus. He is the youngest of the trio formed by himself, Terra and Aqua.

Ventus's heart is severely damaged by the creation of his dark counterpart, Vanitas, and then again when the χ-blade forged from their hearts is destroyed. Both times, Sora's heart reaches out to mend Ventus's heart, and by the end of Kingdom Hearts Birth by Sleep, Ventus's heart has gone to sleep within Sora so that it can recover until it is fully healed and ready to rejoin his body, which lies comatose but safe within the Chamber of Waking.