Here is the full list of all 99 Hero or Villain: Battle Royale achievements.
Defeat Flying Death.
Defeat Ruby Psyche.
Defeat Splash Tornado.
Defeat Earth Rage.
Defeat Blademaster.
Defeat Headshot.
Defeat a Mag'zhar general.
Defeat a guard robot.
Defeat Sonic Fire.
Defeat Rathamiel.
Become an expert shooter.
Become one of the best shooters on the planet.
Become a proficient engineer.
Become the most skilled engineer on the planet.
Become a good fighter.
Become the most feared melee fighter in the tournament.
Become an expert at delivering first aid.
Maximize your first aid ability.
Become proficient with alien technology.
Become extremely proficient with alien technology.
Learn about alien biology.
Become an expert on alien biology.
Possess a strength greater than any creature on Earth.
Possess a strength greater than any creature of legend.
Have agility greater than an Olympic gymnast's.
Have agility greater than any creature on Earth.
Possess far greater endurance than any other human.
Have the ability to take large amounts of damage.
Possess an intelligence able to design alien-level equipment.
Possess the ability to design and operate advanced alien-level equipment.
Develop an iron will.
Develop a will more powerful than any creature on Earth.
Become an established mating-ceremony witness.
Calm a conflict between races.
Instigate a conflict between races.
Find a sage.
Find more about the Lanista's background.
Find more about Thoronium Stones.
Find love under the night sky.
Take a stance against gambling.
Protect gambling institutions.
Defeat a mafia leader.
Become the leader of a criminal clan.
Create a vampire clan.
Eliminate a crime syndicate.
Make the streets of SeoDong safer.
Start your own criminal empire.
Win a bet.
Break into a prison.
Invent a pulse pump.
Invent a plasma cannon.
Design semi-sentient robots.
Develop sentient robots.
Join the rebellion.
Bring chaos to metal markets.
Take over a Mag'zhar army base.
Overcome a defended perimeter.
Win a battle.
Reunite with your team.
Absorb a Thoronium stone.
Turn a colleague into a vampire.
Train a colleague to keep her from getting killed.
Find somebody to help a colleague in need of medical aid.
Sunbathe in the afternoon sun.
Go on a hunt.
Understand post-hunt ceremonies.
Start dating a colleague.
Go see a concert.
Go to a museum.