Here is the full list of all 20 Fourteen Fiends achievements.
Rye!
Rob'o & Pete!
The Bedrock Beast!
Marcel Jones!
Spiteful MAW!
The Pine man!
Valiant!
Boulder!
The MEME Machine!
Gabe
The Coral KING!
Buggy Von Garland!
The Cookie Cooks
Bowler Bot!
The Painting of Felton Thrill!
Professor Blunk!
Gag!
You Won a Round!
You won 25 rounds!
you survived the DOOM MOON