Spirits, they are creatures who don't possess a physical form. They are just there around, without us noticing them. A vague existence, that's what they are…
For us to notice them a Spirit must have a vessel. In this case that vessel would be about the orb the Spirit resided.
"I am the Spirit of the Wind, Sylph" The green haired boy grinned, as he boastfully introduced himself.
I mumbled, "The spirit of the wind..?"
So, this kid is the spirit of the wind. Wait, more than that he is. He is…
"You're smaller than I thought!" I exclaimed. "You are rude for a kid that will meet someone for the first time, you know!" Sylph complained.
Sylph sighed, "Did you think that I would be bigger than my appearance now?" I nodded. "I expected you to be as big as a Giant!" I stated.
"As big as a Giant..?" Sylph mumbled.
I smiled. "I once read in a book that the Spirits' appearance is based on the amount of their Ether" I stated.