Dreams of Mountains, Spirits of the Sea

(No harem, no invincible protagonist, not a wish-fulfillment story, no System. Familiar tropes, but every major plot thread will be resolved.)

How many mistakes can youth afford? How can youth be spent riding a horse among the flowers?

When I thought that entering that world would let me reunite with her,

I discovered I was wrong.

I thought I could leave that world by taking part in its twisted death game.

Instead, I saw the sky collapsing and order being erased.

When I realized it was an epic tale of apotheosis,

I never imagined it was only an illusion that no one cared about.