Metalgelas is an armored humanoid rhinoceros which is Thrust's Advent Beast. Metalgelas later ends up under the control of Kamen Rider Strike, but Strike lost it.
Thrust slots his cards in a compartment on his left shoulder called the Metal Visor.
- Attack Vent: Summons Metalgelas to attack his enemies directly.
- Strike Vent: Conjures a horn-like weapon.
- Confine Vent: Negates the last Advent Card slotted.
- Final Vent: Summons Metalgelas for Thrust's Final Vent. Metalgelas carries Thrust on his shoulders, his Strike Vent weapon equipped, as it pierces his enemies in a high-speed charging attack.
- Link Vent: Unites and unleashes the power of all of 13 Final Vents.
- Metalgelas, derives its name from the Greek river god Gelas. Although many depictions of Gelas are that of a bull-horned man, some contexts refer to is as "head of horns".
- The word Gelas also means mirror/glass in Indonesian and Malay Language as Metalgelas is a mirror monster.