His mother, Sally Jackson, could play an important role as an ally. She has a strong will and has always been there for Percy. Also, Tyson, his cyclops half - brother, could be a powerful ally with his strength and loyalty. And don't forget about the Nymphs. Some of the water nymphs might help Percy since he has a connection to water.
Annabeth is a very likely ally. Their relationship is so strong that she would follow him into Tartarus and be by his side through thick and thin. Grover could also be an ally. He's Percy's long - time friend and his skills as a satyr could come in handy in Tartarus. Nico di Angelo is another possibility. His knowledge of the Underworld and his powers over the dead could be useful in the dangerous Tartarus environment.
Annabeth Chase would most likely be one of his allies. She has always been by Percy's side, and she shares his sense of justice. If Percy decides to take on the gods, she would be there to support him with her intelligence and strategic thinking.
Athena might also be a good candidate. Although she and Poseidon have their differences, she could see Percy's potential and befriend him. She could offer him wisdom and strategic advice for his various adventures.
I think it would be Magnus Chase. Since Magnus has experience with the Norse world and Percy is used to dealing with the demigod stuff, they could combine their knowledge and skills. Also, they both have a sense of justice and would likely work well together.
The Cyclops Tyson could be an ally. He has a strong bond with Percy and his strength could be a great asset. In a fanfiction where Percy is the God of Light, Tyson could be like a protector of Percy's light - based temples or strongholds. Also, the sea creatures that Percy has befriended over the years might come to his aid. Since Percy has his roots in the sea and now has light powers, they could work together in a unique way, like the sea creatures using their natural abilities to help spread Percy's light across the oceans to keep dark sea - based threats at bay.
Grover might be the most likely to resist. He has always been very connected to the mortal and natural world. His role as a satyr has been to protect and guide demigods in the mortal world. Becoming a god would mean leaving behind his familiar role and the simple joys of the natural world he loves so much. He might fear losing his identity and his close connection to the forests, meadows, and the young demigods he has befriended over the years.
Some minor gods related to the earth like Demeter could be allies. She has her own powers over the earth and could teach Percy some of her techniques. Also, the nymphs, such as the water nymphs and the tree nymphs, could be allies. The water nymphs could help with the water sources within the earth (like underground rivers) and the tree nymphs could help Percy take care of the forests. And let's not forget the pegasi. They could be used for transportation when Percy needs to quickly travel across his earthly domain.
Annabeth could definitely be one of his main allies. Her intelligence and strategic planning would be invaluable in a fight against Olympus. Also, Grover might be there, using his skills as a satyr to gather information and support from other nature - related beings. Some of the less - well - known demigods from Camp Half - Blood could also join in, seeing Percy as a chance for a new order.
Annabeth could definitely be one of his allies. She's smart and resourceful, and her knowledge of architecture and strategy would be useful no matter where in the universe they are. She could help Percy figure out the layout of strange alien cities or fortresses.
His friends from Camp Half - Blood would be his allies for sure. Annabeth, with her strategic mind, would be invaluable. Grover, the satyr, could help Percy communicate with nature spirits which could be useful. But also, some of the minor gods who feel left out by the major Olympians might side with Percy. For example, Hecate could use her magic to assist Percy, seeing him as a chance for a new order in the Olympian world. There's also Tyson, Percy's cyclops half - brother, who would be a strong and loyal ally.