Here is the full list of all 23 Diabolical achievements.
He looks the part.
Start a relationship with The Count or Countess.
Learn the Count or Countess's secret.
A little insanity never hurt anyone.
What sort of villain are you?
Life wouldn't be worth living without them.
Start a relationship with Steelheart.
Reunite with an old...friend?
Zombies? No problem.
Cyber-attacks are the way of the future.
Begin your supervillain career.
Some crimes can be ignored.
Have you considered a career in mad science?
Victory goes to your enemies.
Every villain wants to do this, right?
At last, you'll receive the recognition you deserve.
Who says a villain can't have noble goals?
Let's see if people really want freedom from the law.
They'll never forget you if they always see you.
Cartoons are wonderful.
No one has enough responsibility to handle this.
Whatever Arachnus did to Earth, it's been undone.
Power like that isn't worth messing with.