A manic and impulsive criminal from Zaun, Jinx lives to wreak havoc without care for the consequences. With an arsenal of deadly weapons, she unleashes the loudest blasts and brightest explosions to leave a trail of mayhem and panic in her wake. Jinx despises boredom, and gleefully brings her own chaotic brand of pandemonium wherever she goes.
No one knows for sure exactly where Jinx came from, but many urban legends and folktales have sprung up around her. Some have her as a young gang member who fell in with the wrong crowd and was either traumatized by one too many killings, suffered too much at the hands of an enemy, or was simply driven insane by sump fumes. A few of the old timers in Zaun remember a young girl who might fit Jinx's description, but the girl they speak of is a far cry from the one who became Piltover's bane. This girl was sweet and innocent, a tinkerer with big ideas, who never quite fit in and came to a bad end. Some even whisper that Jinx isn't even human, that she is some kind of avenging spirit of mayhem, come to wreak havoc upon Piltover in revenge for the thousands who died when Zaun sank into the earth.
Jinx made her first appearance on Roguery Night, a barely tolerated annual tradition where youthful girls and boys throughout Piltover play practical jokes on their family and neighbors. Jinx hijacked the occasion to unleash the first of many crime sprees; bridges were blocked with stampeding livestock freed from Count Mei's menagerie, scores of roads were shut down by explosions that made them impassable, and every street sign in the city was moved and placed somewhere new. Jinx had succeeded in spreading chaos throughout the streets and bringing the city to a halt. It had been a good day.
The wardens attributed her crimes to chem-punk gangs, rounding up dozens of known troublemakers and sending them back down to Zaun. Having others get the credit for her manic schemes didn't sit well with Jinx, and so she made sure to be seen at every future crime scene. Reports circulated of a mysterious, blue-haired Zaunite girl, but talk of her carrying chemtech, a shark-mouthed and a were dismissed as preposterous. After all, how could a Zaunite chem-punk possibly obtain such lethal firearms?
The crime spree escalated in lunacy until Jinx detonated a series of explosives simultaneously throughout the city. A great many of the civic art structures erected by the Piltover clans were destroyed in fiery conflagrations that lit the sky in blazing pyrotechnics until dawn. Due to the late hour, no one was hurt, but numerous clan leaders were outraged at the sight of their great works reduced to rubble.
Jinx's crime wave continued for weeks, with the wardens' attempts to catch her thwarted at every turn. She tagged her crime scenes with insulting graffiti and taunting messages directed at Piltover's newest ally in the fight against crime, Enforcer. These bright pink tags finally revealed the name of Piltover's newest troublemaker: Jinx.
With every bold crime, Jinx became ever more legendary, with people in Zaun divided as to whether she was a hero for sticking it to the Pilties or a dangerous lunatic that would bring the full force of the wardens down to the undercity. That moment came even closer when Jinx sabotaged the Sun Gates and delayed the flow of ships by several hours - costing the city's ruling clans vast sums of lost revenue.
Having seen exactly which buttons to press, Jinx offered a challenge that couldn't be ignored - she threatened Piltover's money. She daubed the walls of the Ecliptic Vaults, one of Piltover’s most secure treasuries, with a caricature of Enforcer Vi, together with details of exactly when Jinx planned to rob it.
An uneasy sense of anticipation settled on Piltover and Zaun in the weeks leading up to the appointed date of Jinx's heist. Many doubted Jinx would have the guts to show up and risk almost certain capture. When the day of the heist arrived, Vi,, and the wardens were taking no chances and had prepared a trap for Jinx around the treasury. The clocktower bells rang at the appointed hour, but nothing happened. It seemed Jinx had chickened out, but she was one step ahead of her would-be captors.
Jinx, despite the seeming recklessness of her actions, had a plan and it had been in motion for days. She had hidden herself within a modified coin-crate at the Toll Towers of the Sun Gates and had been delivered to the vaults two days previously. Jinx was already inside, and was even now wreaking havoc, leaving her signature pink tags on every gilded wall, swinging from the chandeliers, and leaving explosive surprises in every lockbox.
Hearing the cacophony from within, Vi realized what was happening. She stormed inside the building, ignoring Caitlyn's order to go in as a team. The battle they fought tore the vaults to pieces in a back and forth chase of explosions and demolition. Eventually Jinx and Vi confronted one another in the deepest, most secure vault. No one knows what passed between them, for Vi had pursued Jinx far ahead of the others. With the two of them trapped together underground, Jinx fired her rockets into the ceiling of the vault, and the entire structure collapsed. The wardens in the upper reaches of the vault escaped before the building came down, but Vi was left trapped inside. Only by hiding in the same lockbox Jinx had used to break in was she able to avoid being crushed to death. Eventually she punched her way out from the ruins, wondering for a moment if Jinx lay dead somewhere in the ruins, only to see one last tag left in the patterns of destruction - a final taunt daring Vi to catch her. No trace of the blue-haired hellion could be found, and to add insult to injury, not a single coin had been taken from the vaults.
Jinx remains at large to this day, and is a constant thorn in Piltover's side. Her actions have inspired copycats among the chem-punk gangs of Zaun as well as numerous satirical plays, sayings and the like throughout both cities. Her ultimate end-game (or why she is seemingly obsessed with Vi) remains a mystery, but one thing is certain: her crimes are continuing and growing in sheer audacity.