A Silver Lining

"Four kits of different keys"
"one of silver one of shadows"
"one of flame one of storm"
"These kits aren't as seen"
"Only the silver and flame can truly seek"
"For their name are considered unique"
"The storm and shadow shall rain"
"Only mist can catch the silver while a pelt would match the flame"
"A tail might catch light while the fur would disappear into the shadows"
"These four kits are the key"