There are many special achievements in "Call of Duty: Black Ops 6", and Hidden Spy is one of them. If you want to do this achievement, you can reach the guild in blood and fire without breaking the secret. Meeting, at the beginning of the mission, bring out the guard by the river.
How to get the Hidden Spy achievement in Call of Duty 21 Black Ops 6
The hidden spy
In Bloodfire, reach the guild meeting without breaking the secret
At the beginning of the mission, take out the guard by the river and head towards a river mouth on the left. Swim through the tunnel and after the exit, turn right and head towards the stairs.
After walking up the stairs, turn left and follow the scaffolding. Take out the nearby enemies, then crawl to the open window to your right. After entering, turn right and find a locked bar door. This is the entrance to the clock tower. Climb the ladder.
Once you've climbed up and sniped Yannik on the yacht, jump from the bell tower into the water below. Then follow the same route we took to the bell tower back to the starting point.
After a short cutscene, enter the restaurant from the alley on the left, then turn left at the vent and chase away the restroom security guard.
Lure the two remaining guards into the restroom by making noises or letting them see you enough to become suspicious, then hide back in the restroom. Kill them when they get close. Then he squatted down and quietly walked up the stairs. At the top of the stairs, wait for the guard on the left to turn his back and the guard on the right to walk away, then kill the guard on the left and walk to the door on the left. Terrible achievement :)