Perhaps Naruto's 'dark godlike' status makes him a target for those who want to harness his power in Highschool DxD. This could lead to a series of battles and chases as he tries to evade those who would use him for their own gain. At the same time, he might befriend some of the underdogs in the Highschool DxD world and help them rise to power. He could also introduce new concepts from the Naruto world, like chakra, which could change the way magic works in Highschool DxD.
A potential plotline could be Naruto arriving in the Highschool DxD world and being mistaken for a new type of devil or other supernatural being due to his 'dark godlike' nature. He would then have to prove his intentions and find his place in this new world. Another plotline could involve Naruto using his skills to train the characters in Highschool DxD in combat, similar to how he trained his friends in the Naruto world.
One interesting plotline could be that Naruto discovers a connection between the Highschool DxD world and some long - lost part of the Naruto world. His 'dark godlike' powers might be the key to unlocking this mystery. As he delves deeper into this connection, he has to face both the internal struggles of his own new - found powers and the external threats from the various factions in Highschool DxD. He might also find love or form deep friendships in this new world, which would further complicate his journey.