I'm not sure if there is an exact 'Naruto brother of Zeus' fanfic. There are countless fanfictions out there, and while the idea of combining Naruto and a figure from Greek mythology like Zeus in a fan - created story is very creative, it might be a rather unique and not so common combination. You could try searching on major fanfic platforms like FanFiction.net or Archive of Our Own.
A fanfic about Percy, brother of Zeus, could start with Percy feeling a sense of isolation. Despite being part of the divine family, he doesn't quite fit in. He decides to leave Olympus for a while and explore the mortal world. There, he experiences the joys and sorrows of humanity in a way that Zeus never has. He falls in love with a mortal, which causes a huge rift between him and Zeus. This love story could be the central theme of the fanfic, with Percy having to choose between his family and his new - found love.
The character of Percy's younger brother in Zeus fanfiction could bring new dynamics. He could be a source of conflict, perhaps being jealous of Percy's achievements and trying to outdo him in the world of the fanfiction. Or he could be a support, working alongside Percy against common enemies. It all depends on how the author wants to develop the character.
One possible plot could be Percy, as the brother of Zeus, having to deal with the politics of Olympus. He might struggle to find his place among the other gods while also trying to use his powers for good. Maybe he teams up with some of the younger demigods to bring about change in the rather old - fashioned ways of the Olympian council.
A 'Naruto brother of Zeus' fanfic could be really wild. Naruto has his ninja powers and strong will from the Naruto universe. Zeus, on the other hand, is a powerful god in Greek mythology. If Naruto was his brother, maybe Naruto would inherit some godly powers in addition to his ninja skills. There could be epic battles against other gods or powerful enemies, with Naruto using his unique combination of abilities.
Well, one possible plot could be Percy discovering he's Zeus' brother in a very unexpected way. Maybe through some ancient prophecy that was long forgotten. He'd then have to deal with the power struggles within the Olympian family, as well as his own identity crisis. Another aspect could be his relationships with other demigods changing, as being related to Zeus is a huge deal.
The main antagonists could be some of the more traditional and power - hungry gods. For example, Hera might see Percy as a threat to the order she has maintained for so long. She could try to undermine him at every turn, fearing that his new ideas and his relation to Zeus will disrupt her plans. Another antagonist could be Ares, who might be jealous of Percy's potential power and influence over the other gods and demigods.
The plot might involve Percy's discovery of a hidden power within him. As the brother of Zeus, he has always been in his brother's shadow. But when he uncovers this new power, it changes everything. He has to learn how to control it, and in the process, he may attract the envy or fear of other gods. This could lead to a power struggle within the divine realm.
They could interact in many ways. For instance, Percy's younger brother might be a devotee of Zeus and constantly seek his guidance. Zeus, in turn, could use the younger brother for his own purposes, like having him perform tasks that Percy would refuse.
His powers would likely become more god - like. He might gain the ability to control lightning, like Zeus. Also, his strength and speed could be enhanced to a much greater degree. His control over water, which was his main power before, could also be amplified and perhaps combined with his new lightning powers in some unique ways.