peak human strength, speed, agility, endurance, reflexes, empathy training by Priests of Pama led to telepathy, telekinesis, pyrokinesis, precognition, bio-empathy for both plants and animals, intuitive ability to target weak spots
In-house associate from Avengers (1st series) #114. Granted full honorary membership status as she departed in Giant-Size Avengers #4.
Mantis's birth name is unknown. She would presumably share the surname of her father, Gustav Brandt.
Steve Englehart, Mantis's creator, had tremendous affection for his creation. So much so that he continued writing for her even after leaving Marvel Comics. Englehart reintroduced a slightly-altered Mantis as "Willow" while writing DC's Justice League of America, and then again as "Lorelei" while writing for Eclipse Comics.