User blog comment:Crimson and Darkness/Shin DxD 3 discussion/@comment-77.192.107.58-20190929160022/@comment-95.2.3.146-20191002220143

Issei's body has two different Dragon God powers.

Diabolos Dragon God = DxD - Manifestation of the Power of Ophis

Apocalypse AnswerArms = AxA - Manifestation of the Power of the Great Red

Issei's latest form is the 'Eros Engine', the ExE transformation, which will be the combination of the power of both Ophis and Great Red.