The King of Knights of the Round Table that is described in legends.
In reality, a lovely female-knight, and yet possesses both purity and integrity just like in legends.
She is known as a holy sword-user, but the holy spear she possesses is actually quite powerful as well, making possible to manifest as a Lancer.
---furthermore, it is also possible for her to materialize as the possibility of having been violated by the curse of the Holy Grail like this. The spear-wielding aspect of the King of Knights that persists in being heartless.
Rhongomynyad - The Spear that Shines in the Far Away
Holy spear. Also known as Ron. It has been said that its true form is that of something which fastens together the two sides of the world.
When releasing the True Name, both Rank and classification change.
Originally, this holy spear is the "pillar of light" that sews together the two sides of the world, and it has been said that - in the unlikely event that this is undone - the current world that has been composed by the laws of physics will be torn off, and the many laws of illusion that became things of the past will appear.
Due to being the "king" that stood in the final moments of illusion and the Age of Gods, she possesses this holy spear that conceals such tremendous power.
Unleashing the holy spear’s true name requires the removing of half of the spear’s 13 restraints. Upon this, the holy spear releases a portion of the power drawn from the light shining at the edge of the world. This property is believed to be on the same level as the planet’s holy sword of world salvation.
There are controversial claims that, if summoned to the world as a Lancer, one certain part of the King of Knights would appear different from when she had been alive. Some believe that the possession of the holy spear, rather than sword and sheath, would allow one certain part of her to grow despite her agelessness… Some believe that the power of the spear would allow one certain part of her to age…
Even if she exchanges the holy sword for the sacred spear, the way of being of the King of Knights does not change. She still is the same King of Knights who became a king by acquiring the sword of selection, who opposed assailing foreign enemies, monsters and occasionally even dragons and continued to fight to protect her homeland.
Even upon manifesting as Alter, she will surely become of assistance to the Master in regards the restoration of human history.
Source: translated by Master of Chaos on Beast's Lair