Valkyrie no Bōken: Toki no Kagi Densetsu (Nintendo Cinematic Universe)

Valkyrie no Bōken: Toki no Kagi Densetsu is a Japanese graphic novel.

Summary
A titular Valkyrie must defend Marvel Land from the Zouna.

Plot Elements

 * In Marvel Land, people coexist in peace and harmony with nature, and the animals are docile.
 * Humans, Sandras, Quarkmen, Tattas and other races mingle, working to improve their community.
 * A large clock tower, resembling a stone grandfather clock, stands watch over the countryside; an ancient evil was sealed in the clock long ago with a key of time (stored in the middle of its face), and the people have lost their fear.
 * One day, the clock tower mysteriously stops working.
 * Before long, a villager takes it upon themselves to rewind the clock. Fumbling with the key of time, the villager drops it, and before they can pick it up, Zouna, a dark wizard who manipulates time, escapes and takes the key.
 * Zouna wreaks havoc in Marvel Land, darkening and terrorizing its people and laying waste to the countryside. Confident in his power, he builds a castle, ruins once-thriving towns and villages, and separates families.
 * Only a few scattered towns remained standing, a futile bastion against Zouna's invasion.
 * Even Krino Sandra (known as Whirlo in Europe) would be subdued heroically by Zouna, Marvel Land needs a savior.
 * Valkyrie, a fledgling shieldmaiden descends to Marvel Land from the heavens. In her first adventure, she wields a simple shield and a mace of light. Vowing to save Marvel Land from the darkness which has consumed it, her adventure begins.