Reborn As A Blade Of Grass, I Become The Companion Of A Goddess COAP

Ye Yun transmigrated to a fantasy world. The first thing he noticed was that he was beneath a gigantic willow tree. It turned out that he had become a blade of grass!
[You signed in at the willow tree and acquired the magnum opus of Chan Faction - The Refined Mystic Techniques.]
Thankfully, the village he was in was peaceful. Ye Yun quietly signed in daily and nurtured himself. His only companion was the gigantic willow tree and a kid who always came to play under the tree.
Days passed by and Ye Yun’s cultivation grew more and more profound.
He witnessed the kid growing up. He occasionally guided the kid, so the latter called him Master.
He also witnessed the willow tree grow more and more full of life. He would remove tree stumps for her regularly and pour out his heart in front of her.
One day, the kid returned with severe injuries and told Ye Yun his dying wish.
The willow tree also transformed into a goddess dressed in white robes. As she looked at the blade of green grass beneath her feet, she said, “We have kept each other company for so many years. We are like spiritual partners. Are you willing to follow me to wage war on the Immortal Realm?”
Ye Yun, “...”