Tlotoxl

Tlotoxl (in Azteca, Tlohtoxcatl) was an Aztec High Priest of Sacrifice in the 15th century.

Biography
When Barbara posed as the reincarnation of Yetaxa and called off the human sacrifice of the first victim, Tlotoxl declared her a false god and tried poisoning her to prove her mortality. However, his plan failed when Barbara offered them the drink.

At the solar eclipse, Tlotoxl tried stabbing Barbara, but Ian Chesterton caught him. Ian and Barbara left for the TARDIS, and Tlotoxl was offered the Perfect Victim as a sacrifice. (TV: The Aztecs) He and Tonila later prepared cocoa in honour of vanquishing Barbara. (HOMEVID: Making Cocoa)

Twenty years later, Tlohtoxcatl still held the role of High Priest, as well as being part of the Ixtilque. However, despite his severity, Tlohtoxcatl was popularly perceived as a good man with a strong heart. (PROSE: Against Nature)

Appearance
Tlotoxol was a powerfully built but deformed man with long, matted hair, a hard, thin mouth. and piercing jet black eyes. He wore a loose-fitting robe caked in dried blood and a blood-spattered plumed headdress. He had a limp. (PROSE: The Aztecs)

Momacani described him as appearing totally caked in soot and grime, smelling of body odour and faecal matter. (PROSE: Against Nature)

Behind the scenes

 * Tlotoxl is one of the few Doctor Who villains who never receives any sort of comeuppance. This serves to highlight the themes of the story, that history must not be tampered with, and that it will take its course with or without us. This would be developed in many stories throughout the DWU, perhaps most famously in TV: The Waters of Mars.
 * In Against Nature, Lawrence Burton changed the character's name to "Tlohtoxcatl" in accordance with real-world Azteca grammar. In Burton's self-published Sixth Doctor novel Smoking Mirror, it was revealed that the character died by accidentally sacrificing himself.