Once Horus was grown, he came out of the Delta to claim his right to his fathers "office." This myth, called the Great Quarrel by some, was not a serious one. The story is mostly dialogue. It was created for entertainment; therefor, it is shallow and without real meaning. Nevertheless, it is interesting, and worth mentioning here.
The counsel of the gods was considering giving the office to Set, because he was the larger and stronger of the two. After much discussion and consulting (supposedly, the discussion went on more that eighty years), it was decided to give the crown to Horus. Set became enraged and challenged Horus to a battle in the sea, both of them taking the form of hippopotamuses. Horus accepted. His mother, Isis tried to help him, but ended up not really doing so at all, but rather, made it worse. First, she harpooned him accidentally and released him. Then she harpooned Set, but released him as well because Set was able to persuade her to do so. This angered Horus so much that he came up from the water and cut off his mothers head. He took the head to the mountains to hide from the punishment he had just earned. He hid under a tree in an oasis and the company of gods looking for him could not find him.
Set was able to find Horus, however. He tore out Horuss eyes and planted them the ground, where they bloomed into lotus flowers. Set denied being able to find Horus to the counsel, but another god, Hanthor, found Horus again, restored his eyes, then brought him to the counsel. A truce was called and Set and Horus went off to rest together.
This point in the story is a good example of how this myth was not to be taken seriously. The material is vulgar in this portion. In not so many words, Set violated Horus that night. Horus ran to his mother (who obviously did not die from decapitation) with Sets semen (seed) on his hand. Isis cut off Horuss contaminated hand, threw the hand in the ditch, and put some of Horuss semen on Sets garden. Set became pregnant when he ate from the garden.
Obviously, it was not a moral crime to violate homosexually as it was to be violated homosexually, because Set and Horus went before the counsel and Set declared that Horus was unfit for the crown because he allowed Set to "treat" him homosexually. Horus claimed this was untrue and that the gods should call the "seed" of each to see who had "treated" whom. The gods did so. Sets seed answered from the ditch, while Horuss answered from Set. The gods declared Horus right. However, once again, Set challenged Horus to a contest. This time, it was a boat race in boats made of stone. Horus built his in the night, when no one could see. He made his of wood, but covered it with gypsum, making it look like stone. Set saw the boat, and made his of stone, thinking Horuss was also. The next day, Sets boat sank immediately, of course. He was enraged and tried to kill Horus, but the gods intervened.
After more discussion and consulting, Set finally agrees to let law rule over brute force and resigns. Horus was given the crown, and in compensation, Set was made god of storms. His main duty was to fend off the serpent dragon of darkness, Apopis, as he tried to overcome Osiriss divine barge at sunrise and sunset.
This leads us to the myth of Set and Apopis. The tone of this myth was the same as that of the Great Quarrel; however, it was not told in direct speech, but was an actual dramatic piece. During a confrontation with Set, Apopis insulted and embarrassed Set by mentioning Sets loss of his testicles during battle with Horus. This enraged Set and he wanted to kill the serpent, but was not brave enough to do so face to face. He tricked Apopis into turning his head, then Set cut it off and chopped it up. He was disgraced by this and driven away from the company of the other gods.