Achilles: Mythical Hero - Achilles Tendon

The extremity of the chaos described is suggestive of the level of power only a god would have, which immediately distinguishes Achilles from ordinary mortals.

Here Achilles’ anger is described as rage, a term suitable to describe the anger of a God....

Poseidon was considered to be the bad-tempered, moody and greedy god among the Olympians. Once insulted, he would revenge himself, like he did in the case of Odysseus, who brutally . Poseidon loved to cross the oceans and seas with his golden chariot surrounded by dolphins.

The Song of Achilles by Madeline Miller - Goodreads

Both stories have unique qualities such as dragons in one and multi-gods in the other and that is what makes fictitious stories like these classics.