@Hirorubie Here!
420 words.
[ ] Hero's ruby – Heroism manifest and crystalized in a ruby. A magic only for those that are True Heroes. It's their will, their hopes and dreams, their own Heroism taken form.
The formation of a Hero's Ruby is seemingly random. When someone makes a great act, such as slaying a great beast, saving a princess, or the kingdom, sometimes the individual will find themselves with a ruby in their chest some time afterwards: The process is not painful, happening in their sleep, and it's quite possible for him to not notice it.
When the Ruby is formed, it will steadily grow in power as the Hero keeps doing heroic things. The Hero has innate knowledge of that fact, and of the Ruby's powers, as soon as they notice it's presence.
The Ruby make the Hero lighter, stronger, faster, better in every way, shape and form, on top of that, he gains a power based on the thing that first gave him the Ruby: For example, slaying a tyrant with a sword would give him magical sword skills, saving a princess would give him powers that allowed him to protect others, etc.
As the Hero makes more heroic deeds, the Ruby will start to glow brighter and brighter, (he can deactivate the glow at will) improving all of it's existing effects, while improving their scope. The Hero's sword power suddenly allows him to cut trough time and space, a power that shields him becomes capable of withstanding a dragon's breath, and covering multiple people, etc.
Eventually, the Ruby will enter a so-called singularity: The Hero's body will be unaffected by the material world unless he wishes to be, only magical effects can truly harm him, and even then, even should his body be destroyed, it would eventually be re-made around the Ruby. The only way to truly kill him would be by destroying the Ruby, and even that would require immense work.
It's theorized that with enough heroism, it would be possible to reach a meta-singularity, where even the Ruby itself becomes unaffected by the world, creating the perfect hero. Invincible, untiring, undying.
Should the Hero ever wish to die, the jewel cracks and he moves on from this world, however, should he ever stray from the path of heroism, the Ruby will dim and dim, eventually, it will entirely darken, crack, and shatter.
There are rumors, hearsay, of a Dark Ruby being seen in the world, but surely something like this wouldn't be possible…