Because Achilles is the child of Thetis and Zeus, and he owed her one.
Zeus
No! Zeus does not have any pets and he never will.
Zeus has 2 brothers Hades and Poseidon and he has other "kids"
Zeus' animal symbol is the Eagle I don't know any more sorry.
a chick
Athena was a child by METIS and Zeus. not thetis.
No, Thetis was the daughter of Doris and Nereus.
Thetis does not promise anything, but Zeus does promise Thetis that her son Achilles will be honored.
Zeus, whose throne Thetis had protected by summoning the giant Briareus when the gods had sought to bind him.
She promises to ask Zeus to side with the Trojans in the battle.
Thetis was promised that Achilles would have honor and glory.
To shjow why Zeus a powerful god would make a promise and help the Nereid Thetis.
Zeus had received a prophecy that Thetis's son would become greater than his father, like Zeus had dethroned his father to lead the succeeding pantheon.
Hera made Zeus give Thetis to a mortal man as his wife.
Intervene on behalf of another.
The union will intervene on you behalf if the company tries to discipline you.
No, Achilles is the son of Peleus and Thetis.