Spike's Element

So I wanted to give Spike an element, my own version of a Seventh Element Story. So in this story Spike will find the seventh element story and it stronger than the others are a lone. it would be kinda like how Sunset could use the element of magic alone but not evil.

The back story is that Spike's element. The element of am thinking Bravery, Sacrifice, or something. It was so strong that get burned it's self out of the tree of Harmony and the Princesses Cutie Marks grew in it's place. Spike's element is kinda the cloud sky flame of the group ,a high five for anyone knows what that is. So the 7th element would go from user to user trying to find the perfect user. One with both a pure heart and a body that can use it's full power. One of those users being Star Swirl himself and that being how the Sisters knew were the tree of harmony was.

First the element would look like all the others before the main six touched them/ But When Spike get's the element( Will have to come up with how) it will turn into an emerald flame shape kinda what I think his cutie mark would be if he was a pony. It would have two forms one be a nickles that he would were in his normal infant form but when active it would turn Spike into more of a teen age form but with bigger wings and he has a bipedal and quadrupedal setting to he's form. In these form his element would become an armor plate on his chest with some armor on his arms/legs, claws, tail, back and wings. He's can use magic in both forms. The child would be weaker throw than in the teen form. Also the more Spike uses the powers to extremes and masters it he'd grow stronger as would his infant form.

Also am thinking someone using the Rainbow of Darkness being the main big bad and that's why they need all seven elements to defeat it. Also this might be the Luna pairing one.