Killbus

Killbas (キルバス) is the older brother of the late Evolto, the last known survivor and leader of the Blood Tribe, as well as the main antagonist of Kamen Rider Build NEW WORLD: Kamen Rider Cross-Z. He is able to transform into Kamen Rider Killbas (仮面ライダーキルバス) using the Build Driver.

Character History
Sometime before the start of the series, Killbas was responsible for the destruction of the Blood Tribe home planet, Planet Blood, as well as the one giving them orders to destroy other planets. Before the destruction of said planet, Evolto escaped with Pandora's Box in hopes of making sure Killbas doesn't find it, prompting the latter to search for Evolto.

After the World of Build was merged into the World of Kamen Rider, Killbas arrived via the White Pandora Panel and copies the appearance of Sento Kiryu and later Satoshi Kakizaki. Taking the Build Driver from Sento, Killbas obtains the means to transform into his Kamen Rider form, Kamen Rider Killbas, which is even stronger than Kamen Rider Evol. Killbas plans to restore the energy of the Pandora Box and use it to destroy the entire universe.

Personality
Following his brother's death, Killbas will stop at nothing until he has eliminated the Kamen Riders in the New World. Killbas is even more destructive than his younger brother and wants to destroy the entire universe, himself included.

Powers and Abilities

 * Hazard Level 3+: Killbas has a Hazard Level of at least 3, as shown by his use of the Build Driver. However, his Hazard Level is likely upwards of 5 due to being a member of the Blood Tribe.
 * Liquefaction: Like Evolto, Killbas can become a teal pool of liquid for transportation purposes.
 * Venomous Tentacle: Killbas possesses a tentacle that he can use to inject his opponent with a dangerous venom. This can be countered with the Genius Fullbottle.
 * Shape-Shifting: While his true form has not been revealed, Killbas can mimic any human due to being a member of the Blood Tribe. He first took the form Sento Kiryu before settling on the appearance of Satoshi Kakizaki.
 * Infusion: Killbas infused Sento's pet spider robot with his own essence in order to create the Killbaspider
 * Fullbottle Creation: Killbas created the Killbas Spider Fullbottle from nothing.

Devices

 * Build Driver - Transformation device, stolen from Sento Kiryu.
 * Killbaspider - Kamen Rider Killbas' slot adapter for the Build Driver
 * Fullbottles - Transformation trinkets

Weapons

 * Drill Crusher
 * Beat Closer
 * Kaizoku Hassyar

Portrayal
Killbas is voiced by Anri Katsu (勝 杏里), who previously voiced Roidmude 106/Thief in Kamen Rider Drive. When copying Satoshi Kakizaki’s appearance, he is played by Gaku Shindo (進藤 学), who is best known for his role as from . As Kamen Rider Killbas, his suit actor is Yasuhiko Imai (今井 靖彦).

When copying Kiryu Sento’s appearance, he is portrayed by Atsuhiro Inukai (犬飼 貴丈).