Much of the fort's structure is decayed, with broken doors and missing roofs, though its main walls still stand. The main gate leads north across a wooden bridge to the path up towards the Manamia Trail - the Ruin also has exits to the east and west.
The bandits have made camp in the castle's outer ward, and gather there at night. They can also be found on the main and side towers standing guard.
There is a jetty on the coast which can be accessed by a steep track from the castle.
The bandits, led by Maul, each have names derived from weapons. They are Anelace, Basilard, Caravel, Claymore, Culverin, Falchion, Glaive, Hammer, Lance, Mace, Mercygiver, Pike, Ranseur, Sling and Voulge.
- Salomet's Grimoire may be found at the highest point of the castle. Under certain conditions, such as when attacked, the bandits will hide the chest.
- Chainmail Bracers, Weak Guard or Hunter's Jacket atop the right lookout tower when viewed from the northern bridgeway main entrance.
- Wyrmward Perfume in a chest next to some boxes on the ramp going from the outer ward to the main tower.
- Red Leather Armor, Bandit's Glove, Rose Ring, or Ring of Gules - in a small room within the castles eastern walls.
- In the larger square room in the ruined tower keep: either an Incognito Mask (common) or a Large Coin Pouch.
- Wakestone Shard atop the remnants of the southwestern lookout tower facing the sea.
- Ferrystone located on the tip of a boat at the jetty.
- A considerable quantity of Cloudwine may be found in throughout the castle.
- A Hero's Worth - kill 35 male bandits
- Reclaim the Roads - kill 10 bandits
- Thick as Thieves - kill 10 male bandits for Ophis
- A Troublesome Tome - obtain Salomet's Grimoire
- Smells Suspicious - obtain a vial of Wyrmward Perfume
- No Honor Among Thieves - complete tasks for Maul
- Badge of Vows 67 - on the castle outcrop
- Badge of Vows 79 - on a castle tower
- The bandits at the fort are initially hostile, but will allow the Arisen entry once news of his or her fame reaches them after finishing the quest A Matter of Myrmidons.
- The bandits at Aernst Castle are much like their counterparts, the female bandits at The Ruins of Heavenspeak Fort, and will not normally attack the Arisen unless provoked.
- When provoked they will tell you to "Bogger off.", "Piss off." or "I'll bleed you dry.".
- The Ruins of Aernst Castle (Capcom, YouTube)