Where are the blind box soldiers in the total war simulator?

Demons are sent under the bridge in necromancer 1 map. There is a hole, you can see the tentacles when you go in, and you can unlock a hidden map when you go in the hole where the tentacles extend. When you enter this new map, you are facing your demon statue, and there is a whip behind your head, which is the hidden arm.

The other is under the bridge of the medieval 1 map. You can see a stone gate under the bridge. Stare at the stone gate for ten seconds, and it will open. After entering, you can unlock the map when the ground glows. On the right side of the new map, you can unlock the hidden arm by staring at the floating objects in front of the French window on the floating island.