Here is the full list of all 20 Battle Knights achievements.
You've gotten your feet wet. Aquas has been cleared.
You have cleared the fiery realm of Cinder.
You have cleared the lush realm of Viridia.
You have cleared the desert realm of Dune.
You have cleared the snowy realm of Aurora.
You have cleared the dark realm of Nocturne.
At least you didn't have to worry about drowning.
Looks like you were able to avoid the lava bath.
Nice platforming skills.
Running through a gauntlet is never easy.
Slip n' slide to victory.
Quick reflexes and good timing, you've got both.
You have bested Anger.
You have bested Brawn.
You have bested Honor.
You have bested Valor.
You have bested Power.
Congratulations, you have cleared the story mode of Battle Knights.
You've conquered the rainbow.
Wake up, you've bested your nightmare.