Stellaris

Achievement requires at least 10 espionage missions completed. By default, you will have access to 9 available missions. There are four more that are unlocked at a later stage. The first unlock you will most likely encounter first which requires any crisis to be around (this includes mid game like Gray Tempest). The remaining three unlocks require the Imperium to be around.

For quick achieving:
-Play game on Cadet difficulty (easiest)
-Take the Subterfuge Tradition
-Find a target empire and start espionage early and work your way through the first 9 missions
NOTE: The crisis mission will require a high level on the target empire so starting early on missions is important as it increases Intel cap on empire each mission
-Once any crisis is spawned, you will have a new mission available called Crisis Beacon; run this mission on the empire you have been targeting

Once crisis mission completes, your achievement will pop.

To complete this achievement you need to either be in the end game crisis it be the galactic emeperor.

Usually on the espionage screen for any player there are 9 opperations which is easy enough to do with time. It is very important to keep aquiring assets in order to increase sucess chance and save some time. I have foind the sabotage starbase to be most tricky to get to work, but with enough attempts it will.

There are, at least, 2 other operations you can unlock in order to get to the 10 operations you need. The 1st is unlocked by the end game crisis, where you set a crisis beacon for anothers capitol. This is science bases and very hard, so I try to find a people with very weak encription so it reduces the level.
The other operation comes as the emperor. This stops the nation from using envoys to destablise the regime. I believe this is diplo based for your assets.

The achievement will most lilely pop after you get one of these 2 as have to be late game.