Name: Castle Dungeon Quest.
Reward: mace of the iceborn, 2 crystal coins, 50 small amethysts, castle shield, access to the upper floors of the castle.
Requirements: level 70, Tortoise Quest
Monsters: venomous red spiders, crusaders, tarantulas, executioner arranz.

1. Follolw the map to find the npc Prisoner of the Castle and say:

Hi->quest->cruel->arranz->kill

2. Kill the boss Executioner Arranz he is located north from the NPC, back to him and say:

Hi->mission

3. Now you can go throught the gate and take the reward.