There isn't anything known about his history.
Throughout From Dusk Till Dawn: The Series
In Place of Dead Roads, he was conversing in the bar with Jacob Fuller and Scott before the show began, as Jacob was asking if Doc could give him and his family a lift back to Texas. He then shows his true colors and the two leave the man after realizing his true intentions with Scott.
In Pandemonium, he is then turned into a culebra and rises when most of the patrons are dead. He stands alongside Cannonball and Rianne, eyeing the remaining humans. Richie then activates a stake "bomb" and it hits Doc in the chest, killing him.
He wore a dark coat and a red shirt. He had dark eyes and white-gray hair. He had a white-gray beard and mustache.
While he seemed to be friendly at first, he showed his nature when he asked Jacob about sharing Scott, implying pedophilic tendencies. When he was turned into a culebra, he became more hostile and animalistic.
Powers and Abilities
- Immortality- Culebras do not age or decay and are immune to death by disease or sickness.
- Accelerated Healing- Culebras heal from physical wounds much faster than humans. In addition, chronic illnesses, such as poor vision, are immediately corrected. For example, Richie was shot in the hand and had a large hole that caused him immense pain if too much pressure was applied to it. Upon transformation, the large wound healed rapidly and his vision was heightened, no longer requiring him to wear glasses.
- Superhuman Strength- Doc has more strength than a regular human.
- Shapeshifting- Doc can shape-shift into a reptilian form that is far stronger and more feral than their human form. It causes them to mentally degenerate into mindless animals that can be killed easier as they are not as smart in a fight and are more blood crazed, though when partially transformed, they are simply more aggressive and can speak, while other are more like hungry zombies and even hunt in hoards or packs. They either have flaked or scaly skin with sometimes hardened scales and horns.
- Sunlight- Culebras are vulnerable to the sunlight and will die of exposure to it.
- Staked- Culebras are vulnerable to stakes to the heart, as it will usually kill them.
- Extraction- Doc is vulnerable to heart extraction.
- Decapitation- Culebras are vulnerable to decapitation, but like snakes, they have been shown to still have movement.
- Doc is usually just a nickname or can be short for doctor.