Black Ops 3 has a category of Challenges called “Dark Ops”. These challenges cannot be found out until you have earned them,
Derived from /u/DidUknowiPwn‘s post, this is the entire list of Dark Ops Challenges.
1) Obtained – Earn Dark Matter by earning Diamond Camo on all weapons in the game.
2) 100 Percenter – Complete 100% of all multiplayer challenges.
3) Trick Shot – Destroy an HC-XD with a Combat Axe.
4) Dr. Lung – Kill an enemy underwater when you are both close to drowning.
5) Relentless Killer – Earn &&1 Relentless medals (20 kills without dying).
6) Brutal Killer – Earn a Brutal medal (25 kills without dying).
7) Nuclear Killer – Earn a Nuclear medal (30 kills without dying).
8) Nuked Out – Earn a Nuclear medal in FFA without using scorestreak rewards.
9) Finish the Job – Kill an enemy that survived damage from 5 teammates in the same life.
10) Calamity – Kill an entire enemy team of 6 or more players in a very short time with a Specialist weapon.
11) Frenzy Killer – Earn a Frenzy Kill medal (5 rapid kills).
12) Super Killer – Earn a Super Kill medal (6 rapid kills).
13) Mega Killer – Earn a Mega Kill medal (7 rapid kills).
14) Ultra Killer – Earn a Ultra Kill medal (8 rapid kills).
15) Chain Killer – Earn a Kill Chain medal (9 or more rapid kills).
16) Fresh Start – Perform a “Fresh Start” stats reset. (Thanks to /u/SycoticMantis for providing an image as evidence.)
1) Deresurrectionist – Reach Deressurectionist (level 35).
2) Apocalypse Averted – In Shadows of Evil, help the others.