"Riding home one fateful night, Lux and her horse were attacked by a ravenous sabrewulf pack." What came out of her to drive the wolves off was light, and in Demacia that is a crime. Riot's biography of Lux is built around that one ride home: a Crownguard daughter discovering she carries the thing her kingdom was founded to forbid, and deciding to keep it secret. For anyone thinking about the world of Runeterra as a game, it is also the neatest summary of Demacia's central problem.
Who they are
Luxanna Crownguard grew up in High Silvermere with her older brother Garen, in a family that had guarded Demacia's kings for generations. Their grandfather saved the king's life at the Battle of Storm's Fang; their aunt Tianna commanded the Dauntless Vanguard before Lux was born. Garen joined the military while still a boy. Lux was expected to run the estates in his absence, resented it, and questioned every lesson her tutors gave her, wanting to see what lay beyond Demacia's walls. Few could stay angry at her for long.
Demacia had been founded as a place where magic was forbidden, after magic had once nearly ended the world, and its folktales were about good hearts turned dark by it. Lux and Garen's own uncle had been killed by a rogue mage. Then came the sabrewulves, and the light. She feared she would become evil, or be imprisoned or exiled, or at the least disgrace the Crownguard name. Alone in the family halls with Garen away, she slowly learned her magic instead: bending sunbeams into solid shapes in the courtyards, making tiny glowing figures in her palm, and keeping all of it to herself.
At sixteen she travelled with her parents, Pieter and Augatha, to the Great City of Demacia for Garen's investiture into the Dauntless Vanguard. The city dazzled her. She found the Illuminators, a charitable religious order that helps the sick and the poor, and befriended one of its knights, Kahina, who trained her in the gardens of the Crownguard manor. Spending time in the capital, Lux has begun to see that Demacia's way is not the only way, and to hold her love for the kingdom alongside a wish to see it made more just, and a little more accepting of mages like her.
Where they belong
Riot's faction pages put Lux in Demacia, and the biography never takes her further than its capital. No race is listed; she is human, a Crownguard, and a mage.
Three champions are linked to her. Garen is in the biography throughout, as the older brother she idolises and whose absence leaves her alone with her secret. Jarvan IV is not named; the kings of Demacia are, as the people the Crownguards protect. Galio is not mentioned.
In the Riot MMO, as a guess
This is speculation. Lux is alive, young, well connected and hiding something, which is a quest-giver's profile, and specifically the profile of the person who sends a player into the awkward parts of Demacia: the exile roads, the Illuminators' charity wards, the question of what happens to a mage the kingdom finds. She is not a boss and not a name on a wall. A player who rolls a mage in Demacia, a combination we looked at in Riot MMO classes, would have every reason to meet her; the wider argument is in will champions be playable?.
What we do not know
Whether the game's era, the open question in when is the Riot MMO set?, finds her alive and sixteen in the capital, or younger, or older than the biography goes.
Whether her secret has been discovered. The biography ends with it still kept, and with rumours that magic is rising in the world again.