Ice Fortress
Each wall has two arrow slits. One wall also includes an ice door with an [arcane lock](https://api.open5e.com/spells/arcane-lock). You designate at the time of the fort’s creation which creatures can enter the fortification. The door has AC 18 and 60 hit points, or it can be broken open with a successful DC 25 Strength (Athletics) check (DC 15 if the [arcane lock](https://api.open5e.com/spells/arcane-lock) is dispelled).
The fortress catches and reflects light, so that creatures outside the fortress who rely on sight have disadvantage on Perception checks and attack rolls made against those within the fortress if it’s in an area of bright sunlight.