Taurus Ballista is the Buffalo Lord in the World of Agito and the main antagonist of the "Agito" arc of Kamen Rider Decade.
Kamen Rider Decade
World of the Rider War
Kamen Rider Decade: All Riders vs. Dai-Shocker
Taurus Ballista led a group of monsters to attack Tsukasa Kadoya. However, Tsukasa is brought to his senses by the A.R. Joji Yuki and leaves to go face Dai-Shocker while Joji Yuki stays behind to fight off the monsters. The result of that battle isn't shown.
Kamen Rider × Super Sentai: Super Hero Taisen
Taurus Ballista was part of the Shocker-Zangyack Alliance, appearing among the army of monsters in the final battle against the Kamen Riders and Super Sentai. During the battle, Taurus Ballista can be briefly seen being pushed away by Red Racer.