Alien X (Ben 10 Unleashed), Ben 10 Fan Fiction Wiki

Alien X is the Omnitrix's DNA sample of a Celestialsapien from the Forge of Creation. Alien X is a humanoid alien whose entire body is solid black, excluding his hands, which are white. He has tiny white star-like spots all over his body, giving him the appearance of a starry night sky. His eyes are green and lack pupils, and his forehead bears three horn-like protrusions. Alien X wears the Omnitrix symbol on his chest. Alien X has three personalities: Serena, the "voice of love and compassion"

Kumainto, Ben 10 Fan Fiction Wiki

Ultimate Shocksquatch (Earth-68), Ben 10 Fan Fiction Wiki

Ghostblast (Biomnitrix Unleashed), Ben 10 Fan Fiction Wiki

Humungousaur (B10 Reboot: AR), Ben 10 Fan Fiction Wiki

Alien X (Battle Ben-OH), Ben 10 Fan Fiction Wiki

Beast Atomic Blaster, Ben 10 Fan Fiction Wiki

Ultimate Rath (Aliens Unleashed), Ben 10 Fan Fiction Wiki

Spitter, Ben 10 Fan Fiction Wiki

Elaskimo, Ben 10 Fan Fiction Wiki

Where could the additional aliens of the OG series appear in UAF