Donovan is a dhampir, born to a vampire father and human mother. His mixed heritage led to ostracization during his childhood in a remote village. A traumatic event awakened his vampiric nature, resulting in the massacre of his entire village, including his mother, after which he consumed their blood. Horrified, he dedicated himself to spiritual attonement, traveling to Asia to study with monks and ninjas. This training focused on controlling his dark urges through Buddhist teachings and developing martial discipline.

During his travels, Donovan encountered Anita, a young girl rendered emotionless after her family was slaughtered by a Darkstalker. Recognizing her supernatural potential and seeing his own inner turmoil reflected in her vacant eyes, he became her protector. To provoke an emotional response, he severed the head of her doll with his sword, Dhylec. This act triggered a violent psychic outburst from Anita, which Donovan subdued, interpreting it as proof her emotions could be restored. He invited her to accompany him, both to heal her spirit and to aid in his mission. Anita retained the headless doll, while its head was sealed within Donovan's Iron Maiden device, used for imprisoning defeated Darkstalkers.

Donovan's primary weapon is the Dhylec sword, a mystical blade discovered in the Tibetan mountains. This weapon channels elemental powers, requiring Donovan to use large prayer beads to help contain and balance its immense energy. His dhampir physiology grants him enhanced strength, speed, and the ability to walk in daylight. He can levitate and ride the Dhylec blade for aerial travel. His combat techniques also involve psychokinesis to ensnare opponents and summon entities inspired by Buddhist and Hindu mythology. However, he constantly suppresses his full vampiric form – a demonic transformation with wings and dark skin – fearing the loss of control it brings. Accessing this form increases his power but risks catastrophic consequences, mirroring his past trauma.

His core mission involves hunting Darkstalkers who prey on humans, viewing this not as a profession or sport but as a sacred duty and path to redemption. He seeks to protect innocents and potentially cleanse his own tainted bloodline. Each Darkstalker he defeats risks corrupting him further, as he absorbs traces of their darkness, making his struggle to maintain humanity increasingly difficult.

Different official media depict divergent fates for Donovan. One narrative path shows him sacrificing his remaining humanity to save Anita, successfully awakening her emotions and causing her to cry. Years later, an adult Anita reflects on his absence while Donovan is depicted seated on a throne surrounded by corpses, engaged in an internal battle against his darkness. An alternative path depicts him as "Dee," representing a corrupted future where he succumbed to his vampiric nature. In Dee's ending, he confronts an older Anita, and their fight's outcome is implied through images of Anita visiting a grave. Unused concepts proposed even darker conclusions, such as Jedah defeating Dee and absorbing Anita.

Donovan maintains a solemn and introspective personality, burdened by guilt but driven by a sense of justice and compassion. His relationship with Anita is central, characterized by a deep desire to heal her emotional wounds while shielding her from threats, recognizing her significant latent power makes her a target for entities like the demon lord Jedah.