Jinx Origin Theory
With Singed's new story and all the new Zaun lore on the verge of coming out, I got to thinking about Jinxes origins. While I've got plenty of questions largely related to her and Vi's exact relationship, I want to focus on how Jinx lost her sanity. So here it goes:
What if Jinx was one of Singed's experiments at some point? Maybe he was trying to make a perfect soldier out of someone who was otherwise unfit to be one. This would include making them physically stronger and more durable while also giving them the right mindset to kill. We see several of these things in Jinx to certain extents. For one she is perfectly capable of running around with a rocket launcher and a minigun without problem. Then there's the simple fact that she doesn't care at all if she harms anyone during her antics... so she's fine with killing people. Singed's alchemical experiments could also be used to explain Jinx's skin tone and eye color while her hair could be a result of that or just hair die.
So if this was the case for Jinx, I imagine Singed's experiment was a partial failure. For instance, he made her stronger and capable of killing without remorse; however she clearly doesn't have the discipline of a soldier. While he succeeded in some aspects, her mind unable to keep up with the experiment, thus causing her to lose her sanity and turn into a complete maniac.