Héroes Inmortales XII was a professional wrestling event produced and scripted by the Mexican professional wrestling promotion Asistencia Asesoría y Administración (AAA) or Triple A. The event took place on October 28, 2018, and was held in the Gimnasio Miguel Hidalgo in Puebla, Puebla, Mexico. It was broadcast on Twitch.tv.
- Numbers in parentheses indicate the length of the match.
- (c) refers to the champion(s) heading into the match.
- Faby Apache (c) defeated Keyra, Scarlett Bordeaux and Star Fire in a Four Way Match to retain the AAA Reina de Reinas Championship
- Nuevo Poder del Norte (Carta Brava Jr., Mocho Cota Jr. & Tito Santana) defeated Aero Star, Angelikal & Drago and Mamba, Máximo & Pimpinela Escarlata in a Three Way Six Man Tag Team Match
- Los Mercenarios (El Texano Jr. & Rey Escorpión) (c) defeated DJZ & Laredo Kid and Bandido & Flamita in a Three Way Match to retain the AAA World Tag Team Championship
- Pagano defeated Averno, Chessman, El Hijo del Fantasma, Espectro, Hijo del Vikingo, Kaoz, La Parka Negra, Niño Hamburguesa and Súper Fly to win the Copa Antonio Peña
- Murder Clown & Psycho Clown defeated Killer Kross & Monster Clown in a Domo de la Muerte Steel Cage match
- Dr. Wagner, Jr. defeated Jeff Jarrett in a Lucha de Apuesta Hair vs. Hair match