A hero journeys to the underworld to do battle ....
a hero returns from a long journey only to find that he must face.....
an epic one
The earliest operas often took their plots from mythology, ancient history, or epic poems. These stories were seen as grand and dramatic, well-suited for the operatic form with its combination of music, singing, and acting.
in the Epic of Gilgamesh , the real person who inspired the epic was Ishtar , the goddess of love and war.
no but it might be in the future
No, you'll have to come up with your own plots if you want to become a writer. "Unused" plots are going to belong to the writer who thinks them up, and they're going to write and sell those themselves. Here's a link to show you how writers find ideas for their stories.
The oldest epic poem is Beowulf.
Well this, is a matter of opinion. Some people might think the most epic pic of of animals, some might like country scenes and some might like city lights.
Who knows -Apex
The Gilgamesh Epic, the Mahabharata, and the Ramayana are all very old and undated. I think which is oldest might be debatable.
You might be asking about "Cantar de Mio Cid," by Per Abbad, which was dated 1207 and is the epic about El Cid.
its according to what you think some people might not like it
An epic journey always involves combat with terrifying supernatural monsters.