Forest Dweller

"I can defeat this thing." Death begins to make a remark, but you cut him off.
"OTHERWISE, it will destroy this planet and your job to carry souls will be a lot more complicated."
"...You, a mere mortal, hope to defeat that which I could not? Are you mad, or simply a fool? Perhaps killing you would be best after all."
"I am the savior of mankind. I was sent by god." At this death sneers.
"I have heard of no such rumor, in the afterlife OR here in this filthy world."
"Do I look human?" You emphasize this by moving the vines on your head and flapping your wings.
"...You have the forest within you. That is not enough. You would need the ocean, the skies, the earth, fire, wind... to defeat this."
"Give me a chance. The alternative I think you very well know." Death seems to consider this, then nods (although given its blurred form you are unsure whether it is a nod or not.)
"Very well. Defeat this thing, and I will spare your life. I am, after all, only the entity Death which watches over the Earth... I cannot risk my job jeopardized. I give you luck, child of Adam." With that, it vanishes.
"Child of Adam? Savior of mankind? I cannot believe Death would fall prey to such tricks. Enough is enough, boy. You've proved to be both witty and agile, let's see how your other qualities match up. Are you ready? Are you ready to protect this mud ball planet you call home? Are you ready to die for such a feeble cause?" After a moment, you answer:
"Yes."
"So be it."