|Mass:||2.3 Earth Masses|
The last planet in the Tetanion System, though it is a rogue planet and has no fixed orbit. Its orbital paths generally tend to take to the outer reaches of the system all the way to the centre, where it passes between Tetanion X and Tetanion C, and sometimes between Tetanion C and Tetanion B. Though it has no fixed orbit, its orbital dynamics prevent a collision with the other major planets in the system. However, it often passes by and "collects" many of the tiny "micro-planets" that orbit on the fringes of the system.