The Erdtree of the Multiverse, Starting with Nausicaä of the Valley of the Wind

Mu En turned into a tree.

Fortunately, he wasn't an ordinary tree. He was a tree with merits to his name-an Erdtree that could grow by absorbing runes and faith, spreading its seeds throughout the multiverse.

But when he opened his eyes, he discovered that he had taken root in a barren, lethally poisonous wasteland.

Just as he was about to wither and die from the toxins, unable to find a single believer, a girl named Nausicaä came beneath his canopy.

"Who are you?"

"O lost maiden, have faith in me! So long as you believe in the great Erdtree, all your wishes can come true!"

"Can you help the Valley of the Wind fight back against the Sea of Corruption?"

"No problem! All you have to do is become my follow-"

"Can you help us get more food?"

"Of course. You need only offer your souls-"

"Then can you help us drive back Tolmekia's tanks and bombers?"

"...Huh?"

(Also known as The Erdtree in Hayao Miyazaki's Worlds. Worlds seeded so far: Nausicaä of the Valley of the Wind, Castle in the Sky, Steamboy, Spirited Away, and Harry Potter.)