5. Jocasta

Jocasta is both the real name and super-name of an android character who first appeared in The Avengers (vol. 1) #162 in August of 1977.
She first joined the Mighty Avengers in Mighty Avengers #21 in March of 2009, having previously been granted provisional membership status in the Avengers in Avengers vol. 1 #197 in July of 1980. She has also taught at the Avengers Academy in her time.
Originally created by the villainous Ultron to be his robotic mate, Jocasta changed her ways and used her powers and abilities – which included computer integration, superhuman strength and durability, enhanced senses, optic cannons, force field generation, and a holographic disguise projector – to do good, and became a superhero.
And now we move on to a character who is far more famous for being a member of a completely different superhero team.
