David is an immortal being who has lived on Earth for centuries in the form of a teenage dark haired boy. He operated in the world as a hero who sought to stop the forces of evil that operated on Earth. In his life span, he had witnessed a great number of historic events that included empires being brought down to their knees, Leonardo's wings, and even heard Hitler's lies. At some point, he also became the mortal foe of the serpent race who had desired the conquest of Earth. He would encounter a secret group of individuals with plans for world domination known as the Organization. On several occasions, he would fight this small band of ruthless individuals where he managed to thwart some of their schemes. In 1958, he thwarted their plans to start a nuclear war and later he stopped their assassination attempt on the French President.
By the modern day, he went by the name of Davy Tenzer who was seemingly the son of Mr. Jesse Tenzer and his wife. Jesse Tenzer was a close associate of Oliver Queen and called him along with Dinah to meet him during an event that Davy had secretly arranged. In that time, a number of murders had been happening in Star City where the perpetrator killed his victims with a black stone thrown by a sling at them. As Green Arrow and Black Canary, the pair would encounter the killer who revealed himself as Davy Tenzer who had orchestrated the deaths in order to bring the pair of superheroes to help him in stopping the Organization's latest ploy that was the detonation of a nuclear weapon.
During his time with Green Arrow, Oliver Queen would not believe the teenager's claims of immortality but would work with him in fighting the Organization. Their encounter would see the three captured though the heroes would escape though the villains managed to detonate a bomb in their base to defeat their enemies. Only Green Arrow and Black Canary seemingly survived where they lamented the death of Davy Tenzer with Oliver Queen believing him a misguided hero. Unknown to them, Tenzer had survived the explosion where he simply walked away with his harp. Afterwards, Davy Tenzer was in Florida where he stood not too far from Supergirl in her civilian identity when she was mind controlled by the serpent man Beriak in his human guise. Beriak sought to prepare Earth for his people's invasion with the help of the mind controlled Supergirl but it was Tenzer's musical lyrics from his harp that removed the domination over her mind.
Davy Tenzer was created by Elliot S. Maggin and Mike Grell where he first appeared in Action Comics #450 in the back-up feature in a three part story arc. He would later appear in The Superman Family #174 in the first story arc with Supergirl where he plays a supporting role in the background and is referred to as David. There are implications during his appearances that he is actually the Biblical David and is seen using a sling and shoots black rocks with it.