Apollo might be the betrayed god. He could have been tricked by another god into betraying Percy. For example, Apollo might have been promised more power or a higher status among the gods if he turned against Percy. But then he realizes too late that he's been used and that he's actually betrayed someone who could have been an ally.
He could be betrayed by a false friend in the DxD world who spreads lies about him. For instance, telling others that Naruto has a hidden agenda to take over their realm.
A possible plot twist could be that the god who betrays Naruto is actually being controlled by an even greater, more malevolent force. So Naruto, instead of just fighting the betraying god, has to figure out how to deal with this underlying evil. Another twist could be that the god's betrayal was a test all along, and Naruto discovers this at the last moment when he's about to defeat the god.
There are many directions a 'betrayed Naruto by a god' fanfiction could take. It could explore themes of fate and free will. If a god betrays Naruto, is it because Naruto's actions were going against some pre - ordained plan? Or is the god simply acting out of malice? Some fanfictions might show Naruto struggling with his belief in the world and the people around him after such a betrayal. He might question his own purpose and the fairness of the ninja world. As for finding a specific one, you could try searching on fanfiction - specific websites using keywords like 'Naruto betrayed by god'.
In a more complex scenario, Naruto could be influenced by an outside force. Let's say an enemy of Konoha uses mind - control or some form of manipulation on Naruto. They make him believe that the ANBU is the enemy of the village and that he needs to take them down. As he betrays the ANBU, he slowly starts to realize that he's been used, but by then he's already in too deep and has to find a way to fix the situation and regain the trust of his friends and the village.
In this fanfiction scenario, Naruto's betrayal by Akeno could be due to a misunderstanding of their goals. Maybe Akeno has been influenced by some dark forces that made her turn against Naruto. It could also be that there is some hidden information that led to this sudden change in their relationship.
In fanfiction, Naruto being betrayed by Akeno could be a very interesting plot twist. It might start with Akeno having some hidden motives or being forced by an external power to turn against Naruto. Maybe she was blackmailed into doing so. This could lead to a whole new set of adventures for Naruto as he tries to figure out why she betrayed him and also deal with the consequences of her actions.
Naruto would likely be deeply hurt. He is a character who values friendship and loyalty highly. Being betrayed by someone he might have considered an ally like Rias would be a huge blow to his emotional state.
Sasuke could also be a character who is frequently betrayed in these fanfictions. Given his complex personality and his history of being both a loner and a seeker of power, he might be lured into dangerous alliances in the DxD world. And his partners in the DxD world could betray him when they realize they can't control him or when his power becomes a threat to them.