Arkus is a Guardian Spiral Knight who went rogue after he lost his comrades in a battle against Dust Zombies. His self-loathing and misery transformed him into a Trojan-like being, only much more dangerous. He appears in the Spiral Knights mission rank 9-1, The Silent Legion.
The Spiral Knights are sent to bring him back home to safety, but he is eventually revealed to be the main antagonist of the mission.
The Silent Legion[]
Throughout the mission, he leaves the Knights messages saying that he is filled with shame and regret, and no longer wants to be a burden upon any of them, and that he belongs with the stone Trojans.
In the eyes of these silent warriors I see myself: cold, strong, unflinching... and crumbling. I have been asked to let it go, to move on, but this I cannot do.
Their faces, their dying cries... they haunted me in my dreams, so I no longer sleep. Now I see them when I close my eyes, forget not blink.
Upon being confronted by the Spiral Knights, he warns them to leave him be, and that he will never return with them. When they persist once more to return him to Haven, he tells them that they are about to learn the same lesson that his team member did: that those who are around him die.
The Spiral Knights are forced to battle him, and he fights in a similar way to them, using Sparks of Life to revive himself. Unfortunately for him, his third defeat is fatal, and he passes away sadly on the ground with his eyes fading.