Santiago Avida was a famous pre-War painter. His most popular paintings were that of cats, although he sold those under an alias. Under his own name, he would rather paint paintings with deeper subject matter than just cats. After Bert Riggs convinced all others to turn themselves into robobrains, he resided within Vault 118 as one. Since then, he has developed a crush for Gilda Broscoe, and has had an affair with her for over "a few dozen years."[1]
By looking at his gallery, it is revealed that he painted most, if not all, of the paintings that can be crafted in settlements.
An unused human version of Santiago can be found in the Creation Kit, wearing the red frock coat and tricorn hat. In fact, all Vault 118 residents have an unused human variant, including the cut Spencer Lords.