The Ru Rangers was a Self Blitz turned actually somewhat trying hack where I have attempted to implement Engage-Ring mechanics into Fire Emblem.
The story revolves around some Forum users post Dies Emblem where they decide to SPEND Christmas together. For reasons, they end up having to save the GREAT STATE OF NEW MICHIGAN from the Grinch Knights once again.
Each character alone kinda sucks, but get them to Engage Ring level and they will turn into promoted forms and gain stats/items for 3 turns, only to be changed back into their normal state until you can get them to secure 3 KOs from enemies. Vulneraries are essentially full heals in this game.