Heroes Vs Villains is a 6 v 6 game type where 3 of you randomly spawn as one of the Imperial and Rebel Hero characters and the other 3 spawn as troopers so being a hero in this mode is random and you might not spawn at the start of a round as a hero, if you don't then you might the next round. Once you spawn as a hero its your chance to try and kill another hero character.
The heroes are:
Rebels:
• Leia Organa
• Han Solo (The WORST for this achievement if you're playing as them but easiest to kill too)
• Luke Skywalker
Imperials:
• Darth Vader
• Emperor Palpatine
• Boba Fett (The Imperials Han Solo though hes a bit better, hes the easiest to kill)
Here's a video where I managed to kill all 3 heroes