The Cancer Vertex (キャンサー・バーテックス) is an enemy of humanity, and the third Vertex the Hero Club encounters. It is based after the constellation Cancer the Crab.
The Cancer Vertex is a predominantly pink and Vertex with, with a multilayered body and head. It's most notable trait are the six retractable fan-like projections.
It's bottom represents a crab and the arms seem to represent the crab's pinchers.
Its six fan-like projections float detached from the main body, and are individually controlled to serve as powerful shields, and perform blunt-force slam attacks.
This Vertex serves as the defense/utility for the trio of the Scorpio, Cancer, and Sagittarius Vertexes. Its six fan-like projections are each controlled independently to shield, and, more notably, to reflect and redirect the Sagittarius Vertex's hails of needle-like projectiles. On its own the Cancer Vertex poses very little threat, but when united in its trio, it allows the Sagittarius Vertex to fire at angles which would be otherwise impossible, such as around corners, in different directions simultaneously, and at multiple targets.
Works in tandem with the Scorpio Vertex and the Sagittarius Vertex in order to destroy the world.
- This Vertex was able to block a full-force attack from Karin Miyoshi's Mankai with two of its fan-like projections. These projections were subsequently shattered with a downward, double kick.
- This Vertex's soul is located within its multilayered, red head; its interference tactic is agility. When presented with the stimulus of an attack, it will dash a short distance in a single direction.
- Yuna Yuki's punches proved insufficient to destroy this soul:
- Yuna Yuki "Huh? Hold still! This soul is too fast, it keeps dodging out of the way!"
- Fu Inobuzaki: "Yuna, switch over! You can dodge point attacks, but I can take you down with an area attack! Take that! First one down!"