He was traditionally the son of King & St. Constantine but probably succeeded an elder brother called Gerren, as King of Dumnonia. Like his predecessor, he was said to have been killed fighting the armies of Bernicia in the North of England. In 613, King Aethelfrith of Bernicia had invaded Gwynedd in order to stop King Iago restoring his old enemy, Edwin, to the Deiran (East Yorks) throne. The armies of Gwynedd, Powys, Pengwern & Dumnonia rose to repel him, but were bitterly defeated at the Battle of Caer-Legion (Chester). Kings Iago of Gwynedd & Selyf Sarffgadau (Battle-Snake) of Powys were killed, and it was probably left to Bledric to command the British forces at the Battle of Bangor-is-Coed (Bangor-on-Dee) that followed shortly afterwards. It was there that the Dumnonian King met his maker. He is said to have been succeeded by his son, Clemen.

Bledric only really appears in Geoffrey of Monmouth's 'History of the King's of Britain' and is generally considered legendary.