User blog comment:B214/Light Novel Volume 16 spoilers/@comment-1359322-20140128102256

"“There is even a radical opinion from a certain mythology where they won’t think twice about sending their military forces into this matter. Chief Gods such as Odin and Zeus are giving their warning to that mythology somehow……but I won’t know what will happen if a terrorism greater than this incident continues even more. After all, the Evil Dragons that are deemed as dangerous from each mythology are causing havoc at once. And the one leading them is the actual son of the previous Lucifer. Even those who saw the previous incident of the Underworld’s monster crises as merely something outside their bounds are feeling that this incident is a serious issue. —If the 666 gets revived and starts a fight with Sekiryuushintei Great Red, the world may collapse due to their aftermath.”

[—!?]

Everyone becomes speechless at Sensei’s confession.

……If Great Red starts a battle with 666, the world may receive that much damage. Yeah, no wonder the higher-ups of each of the factions are making their actions!

The world may have received that much damages if Great Red and Ophis had a battle. However, that didn’t happen. The leaders of the Khaos Brigade till now had been deceiving Ophis and was using her, but they didn’t let her fight Great Red because they knew it was dangerous."

You know reading this part made me think, maybe it's not that Ophis couldn't fight Great Red and defeat him, but she can't fight him because of the aftermath it might result.