Golden Age Arc
During Eclipse, it was Ubik who convinced Griffith to continue walking towards his dream.
The Black Swordsman Arc
Ubik appears with the rest of the God Hand when they are summoned by the Count after he is beaten by Guts. During this sequence, Ubik is the one who reveals to Theresia the true fate of her Mother.
Tower of Conviction Arc
During the Incarnation Ceremony, Ubik, along with the other members of the God Hand, briefly manifested using the dead body of The Imp (Bishop Mozgus's disciple) and several of the evil spirits that had gathered in order to witness Femto's rebirth.
Ubik is also shown when the World Transformation occurs. He is seen surrounded by many images taken from the "Hell" panel of an actual painting, done by Hieronymus Bosch, named "The Garden of Earthly Delights." Both the panel and the painting depict many fantastic yet disturbing visions that could represent Ubik's nature and purpose, one of the more interesting things being the giant tree man he rides in, believed by many to symbolize the Antichrist (a similar figure Ubik could very well have made Griffith into).