The Descent
/By that point in the narrative, no one is surprised when Odysseus enters the Underworld. Having contended with Gods and fought alongside Heroes, Illiad's protagonist displays a heroism that goes beyond the normal ken of man.
This was a recurring theme in ancient myth. Having performed great worldly feats, the hero is tasked to perform something otherworldly. It represents the second-half of his journey, wherein he obtains some great boon for tribe/nation/people.
In creating our myths – in making collaborative roleplay – we need to understand this most important event in the heroic cycle.
For me, it's the deciding factor in character creation: a transition from the conceptual realm and into the actual; wherein the character is no longer a soldier-fisher-whatever, but a character, a name. It's when the story starts to become more deliberate, and the events more pressing. How this manifests, exactly, depends upon the story, but in mythical terms, it's typically with a descent into some other-realm, of which Odysseus' is but one example.
Your characters – the heroes of your myth – are going to undergo these same challenges. They will descend into some underworld, encounter some supernatural force, and ultimately experience a change in themselves.
Perhaps the underworld is a literal one, wherein the characters enter some magic other-realm. Maybe it is metaphor; but a low-point in their emotional history, such as we'd encounter after some great failure or calamity.
The retrieved boon is often thin and inconceivable. Sometimes, it's little more than an affirmation of previous goals – the boon, in this case, being a return to form. Such things will vary from one setting to the next, but the hallmark of these places is such that it causes some fundamental change in the character.
For the inexperienced, this can often be the smooch of death. Their characters no longer adhere to that first imagined draft. They decide it's better to start over, to try again.
I've experienced this in my own time. Characters undergo some challenge, changing something latent to their concept, and suddenly I can't do anything with them. For a long time, I mistook this change as something detrimental, thinking I'd lost something inherent to my storytelling or the character. It lead to a lot of wishy-washy characters, half-told stories, and a general loss in interest in the craft itself.
For us storytellers, this is our underworld; the low-point in our craft. In such a transitory craft as roleplaying, this moment is often the last before the fall, wherein the collective group disperses, and stories remain untold.
Take heart from this time, though. Step away, and look at the greater picture. Have your own characters not endured such pains? Have they not overcome something greater? A boon waits for you, at the end of these creative lulls, and it is the power of perseverance.
Study it well. Someday, you'll have your own underworld to crawl out of.