Only two have ever travelled to the lost city of Icathia and returned. But they are not the only ones to have emerged from that dark and dangerous place. Xin'Jin stepped out of the city soon after Malzahar left it.
There are no records of any explorers there foolish enough to take their children with them. That anybody could have survived for long in that place, especially at such a young age, is beyond belief. If her parents do remain within - if indeed she ever had any - none can say.
The Void has allowed this child to walk Runeterra. And that can only mean she is part of some greater, deadly scheme.
Xin'Jin is a powerful mage and melee fighter whose deadly portals can be used in many potent ways. She can go to the jungle and build as a melee assassin who can use her portals to gank enemies and her slows to secure the kill before portalling away. Or she can build as a long-range mage, using her Annihilation to nuke enemy lines from far away, and harrassing with her portals. Her teleportation and Wormhole can make her a powerful support that can keep her teammates safe from harm, and she can use them aggressively to peel.
In the laning phase as a mage or support, Xin'Jin can combine her two portals from level 2 to peel or nuke, becoming a dominating lane bully. Don't be afraid to take the fight to your enemy, but be careful of the long early cooldowns on her portals should you need to escape in a hurry.
In team fights, try to peel with her portals, or poke using Annihilation. Keeping portals handy for protecting your carry may be useful, or she can use them to engage on the enemy backline herself, or enable her allies to do so.
With Xin'Jin, the options are endless!