User blog comment:B214/Volume 23 discussion blog/@comment-82.178.103.238-20170802211752/@comment-10330822-20170805215730

You're not paying attention. Its a "complete" CxC Mode, which Issei doesn't have right now. When Issei was fighting Apophis, he's still hadn't mastered CxC yet, so he's not using Ddraig full power. We are talking about how strong CxC can be if Issei had mastered it, which the answer is it would be as strong, if not stronger, than Juggernaut Drive.

Think of it like this, Juggernaut Drive, you get the full power, but at the cost of sanity and life. At CxC mode, you get it under your control, but you have to perfect it to get it at the same level. In other words, right now CxC doesn't equal Juggernaut yet, but once Issei trains it enough, it will. That is its full potential, Ddraig's complete power.

As for the other anon's question:

We don't know what Issei can do without BG, for all we know, he can only use Dragonification and Flame Blaze. There is no DxD mode without Boosted Gear. All of these forms are stacked. CxC = BxB + Evil Pieces, DxD = CxC + Ophis's power.

Now, maybe AxA is something that doesn't include Boosted Gear, just makes use of Issei's true dragon flesh. Hence why the form is in front of BxB in order.

To me, if something is called AxA, than that means its something that BxB, aka Scale Mail, will eventually stack over. Similar to how CxC and DxD stack over BxB. Hence ExE, with stack over all four, AxA, BxB, CxC, and DxD, to achieve an ultimate form, so to speak.

I would rather people stop asking about AxA and ExE like we know something, nothing as been revealed other than the names. The only hint that Ajuka gave Issei is that Ophis's power has mutated all ten of Issei's evil pieces, and Issei needs to make "proper use" of these powers to utilize the potential of his true dragon body.