I received one last memento from Peter. He left a package on the doorstep for me. I opened it and discovered a Halloween skeleton mask, and a letter. The letter said Sowing Season had one final component to it; the transference of the negative energy into a physical object.
Grey is inside of this mask. Peter said he didn't tell me at first because it's a lot of responsibility, and that he was searching for a way to safely destroy the object without letting the negative energy, Grey, leak out into the world. Now that he can't, he's entrusted Grey with me, and said that as long as I keep the mask safe, and yet at a manageable distance, everything will be fine.
I'm keeping the mask hidden away.