Nearly everyone has heard the tales of Zeus, Poseidon, Hades, and the other Greek gods. Even if they’ve never read or listened to the original Greek myths, they’re still familiar with the gods through video games, movies, and even music. However, some things about the gods remain a mystery, such as whether or not they are immortal.
Greek gods are immortal; they cannot die, and there are no stories of them being killed. They can, however, be injured, overthrown, defeated, or punished in horrible, painful ways.
The rest of this article will explain how Greek gods gained their immortality and why they feared things despite it. The final section will also discuss the Greeks’ closest thing to a god (or goddess) of immortality.
Also see Why Do Greek Gods Look Like Humans? to learn more.
How Did Greek Gods Become Immortal?
The Greek gods were immortal because that’s how people needed them to be; their immortality was what set them apart from mere mortals. That’s how people told stories about them.
Aside from rare instances, there’s no “origin story” for the gods that talks about how they became immortal. However, the Greek gods most likely retained their immortality by eating ambrosia and drinking nectar, the food and drink of the gods. Ambrosia kept them young, healthy, and alive forever.
While most Greek gods were “born” immortal and only used ambrosia and nectar to retain their youth and immortality, there are a few exceptions. Dionysus is the most notable of these. 
He was the son of Zeus and a mortal woman, making him a demigod, but no matter which version of the Dionysus myth is told, he is granted the gift of godhood during his “second chance at life.” 
Some other beings and demigods eventually earned the gift of immortality or godhood. Some of these include the following:
- Ariadne: The wife of Dionysus; made immortal so that she could live by Dionysus’ side forever.
- Asclepius: One of the most skilled physicians in Greek mythology; Zeus killed Asclepius because he learned to heal the dead. His father, Apollo, retrieved him from the underworld and made him a god in Olympus.
- Ganymede: A Trojan prince; some myths say that Eos kidnapped him along with Tithonus*. Others claim that the god Zeus admired him for his beauty and made him his immortal cupbearer.
- Helen of Troy: The face that launched a thousand ships; Helen and her original husband Menelaus were granted the gift of immortality and sent to live forever in the fields of Elysium after the events of the Trojan War. 
- Heracles: More readily known as Hercules in Roman mythology; because he was one of the greatest Greek heroes that ever lived, Athena came to him after his death and granted him immortality. He even married the Greek’s goddess of immortality, Hebe.*
- Psyche: The lover of Eros; after many trials and tribulations, Aphrodite – Eros’ mother – made Psyche immortal so that she could live forever with Eros among the gods.
*Both Tithonus and Hebe will be discussed in later sections.
Many other beings eventually became gods or gained immortality, but for the most part, the Greek gods – at least the ones most people recognize – seem to have been “born” immortal.
Also see Did Greek Gods Marry Humans? to learn more.
If Greek Gods Were Immortal, Why Did They Fear Anything?
Greek gods may not have feared death, but they were still susceptible to other bad things. For example, being immortal didn’t mean the Greek gods couldn’t be hurt, exiled, defeated, or otherwise damaged.
There are plenty of myths about the Greek gods suffering injury or the wrath of other gods. Hephaestus, the god of blacksmithing and the forge, was widely known as the lame god because he had a severe deformity.
Various myths tell the story of his lameness differently. Some claim that he was born lame, which caused his mother to hate him; others insist that he became lame after an injury incurred when Zeus threw him from Mount Olympus. Either way, he suffered from severe and permanent damage.
Furthermore, while Zeus, Poseidon, and the other ten Olympians are the most well-known Greek gods, they weren’t the only ones, nor were they the first. The Titans came before them, but the Olympians, led by Zeus, destroyed them. The myths never explicitly say that they killed the Titans, but they get rid of them and take over as the ruling elite.
There were other gods before the Titans, as well, and the lead Titan, Cronus, overthrew them, too. Additionally, Zeus’ punishment of Prometheus once Prometheus gave fire to men was brutal.
Prometheus was chained to a rock, and every day, an eagle would come and eat out his liver. At night, it would grow back, and then, he’d have to suffer the same punishment again the next day. While he never died, thanks to his immortality, he suffered immensely, and it was a grave warning to all the other gods not to anger Zeus.
And these are only a few of the many examples of what Greek gods had to fear.
Also see Why Are There So Many Gods In Greek Mythology? to learn more.
Who is the God of Immortality?
A quick Google search for “Greek god of immortality” yields this result: Tithonus. However, strictly speaking, Tithonus was granted immortality; he was not the god of immortality.
His story, however, is an interesting one. He was a Trojan prince kidnapped by the goddess of the dawn, Eos. Because Eos was so in love with Tithonus, she asked Zeus to make him immortal so that she could love him forever.
Unfortunately, she neglected to ask for eternal youth, so his immortality didn’t work out very well for him. He continued to age and age until he couldn’t even move. Eventually, Eos, taking pity on him, turned him into a grasshopper to preserve his life.
The Greeks didn’t actually have a god of immortality. They had a goddess, Hebe, who was the daughter of Zeus and the cupbearer of the gods. As such, she brought the gods their ambrosia and nectar. She and her Roman counterpart, Juventas, were the goddesses of youth and rejuvenation.
Because Hebe continually brought the gods their rejuvenating food and drink, people sometimes consider her as the goddess of immortality. However, it’s important for people to remember that she didn’t grant immortality. She simply acted as a cupbearer, delivering the means of immortality to the gods.
The Greek gods were immortal and had no reason to fear death. However, that didn’t mean that they didn’t fear other things.
Also see Why Are Greek Gods So Cruel? to learn more.