Designation: Advent Master
Advent Deck: Void Key
Eubulon is originally from Xaviax's planet Karsh, and help him build the transportation devices. He had a change of heart while on Ventara and created the Kamen Riders so the Ventarans could defend themselves. He fought Xaviax to a draw, thinking he would be vented, he ended up being found in Roswell on Earth. He warned the No-men of Xaviax upon his arrival but was injured badly and was unable to tell them anything else. The No-Men cryogenically froze him and Len was brought in to reactivate him sixty years later. Eubulon had created the Advent Void for injured warriors but once he was gone, everyone was to be trapped in there. The Advent decks do have DNA lock but Eubulon can change it. He assigned the Siren deck to Maya while Len was the only Kamen Rider available while he got Ventaran Riders out of the Void. He then got Chance, the original Torque; Price, the original Strike; Hunt, the original Axe; Kase and Kit out of the Void. His Void Key has been damaged since his fight with Xaviax, so he has to wait a while until he can go back into the Void to get all the Riders out. He is determined to get all the Riders out. Eubulon gave Kit the Onyx deck because Adam had the dragon deck. Eubulon let Adam in their group in order to hear him out, even though he betrayed the Riders. Eublon created the Link Vent card for the Final Vents of all the 13 riders to be used in order to destroy Xaviax once and for all. Eubulon took everyone out of the void, erased the Earth Riders' memories, cured Chris' asthma, and helped transport the Ventarans back from his home planet of Karsh.