Here is the full list of all 15 Fallen Threats achievements.
It was so easy! Huh?
Good luck!
The patience is the key.
Am i the threat?
What a treasure!
What a good feeling!
This place is very dark.
Well...
You are a true knight!
Kill a bloody snake.
Reach level 5.
Reach level 10.
Reach level 15.
I'm the king of the 30!