After obtaining the Extremer Driver, Argos becomes Kamen Rider Extremer.
Argos was the first born son of Gamma Emperor Adonis and his wife Alicia. After his mother passed away, Argos soon died as well from illness. Their deaths would lead Adonis to vow to create a perfect world free from death.
Kamen Rider Ghost: The 100 Eyecons And Ghost's Fateful Moment
Argos was later revived and given a Ghost Driver from Sennin. Vowing to collect every Eyecon, Argos sent his Dark Necrom minions to obtain the heroic Eyecons.
Chou Super Hero Taisen
Kamen Rider Zi-O
Kamen Rider Drive Saga: Kamen Rider Brain