Ruseato of Seven Prison is a powerful Full Raid level monster that appears in the quest The Nine Prisons of Heroes. Located in the seventh prison, the Prison of the Knight, Ruseato is a powerful opponent that can only be defeated by using a proper battle strategy.
The Prison of the Knight activates a seal that paralyzes all Healer and Mage type players within the party. To undo the seal, certain mechanisms need to be activated. However, this also activates Ruseato's White Knight or Dark Knight forms that have the ability to use Magic. In the Abyssal Shaft raid, although Ruseato doesn't seem to have the seal, he is capable of activating his White Knight/Dark Knight forms at will.
In addition to the halberd attacks, it has mastered the use of <Black Knight Mode> and <White Knight Mode> which was limited by a gimmick in "Nine Great Prisons of the Heroes". Furthermore, armor peels off according to the damage accumulated and produces minions called Shadow Vanguard, changing to <White Knight Mode> in the process, and recovers HP whenever a Shadow Vanguard is defeated.
Towards the end of the raid Shiroe and others were fighting in, Ruseato recklessly pierced its own body, continuously creating Shadow Vanguard.
Gold of the Kunie arc
The Nine Prisons of Heroes bosses were recycled for the Abyssal Shaft raid that Shiroe, Naotsugu, Demiqas, Tetora, and Silver Sword went on. Although they were well-equipped to fight Ruseato, they are completely annihilated when two of the other raid bosses, Ibura Habura of Third Prison and Tarutauruga of Fourth Prison, leave their areas to aid Ruseato, ending in a complete raid wipe.
In the rematch, they initially challenge Ruseato, but escape through a narrow gap made by slicing a bar in the gate to Ibura Habura's zone. However, in the middle of the battle between Ibura Habura and Tarutauruga, who had joined, Ruseato intervenes using its shadow warriors, revealing that the raid boss had injured itself to spawn shadow warriors that could slip through the gate like the raid party had.
Despite this, the raid team manages to defeat Ibura Habura and Tarutauruga as Shiroe successfully negotiates with Kinjo, and Kinjo makes the area a safe zone, dispelling Ruseato's threat.
- Moonlight Death Knell
- Brandishes its halberd and slices down in the area around itself. Has a high critical rate, and will instantly kill on a direct hit on low HP or rearguard members.
- Drop of Perpetual Darkness
- The area of <Ruseato of Seventh Garden> gushes with pitch black swampy liquids, limiting both movement and attack speed, the zone turns into one where damage is reduced.
- Ruseato's Moon Shadow
- The outer layer of dark purple armor peels off, summoning a certain amount of <Shadow Warrior>s when Adventurers hit Ruseato.