Heather's two fathers, Jiminy and Timothy, knew each other for several decades prior to her existence. Since 1940, the two have been heavily involved in a company founded by a man named Walt Disney, both involved in the show business via films, songs, TV shows, the circus, and other forms of entertainment. However, despite being good friends, Jiminy and Timothy nearly always argued with each other daily, getting into spats about the oddest of things. Nevertheless, they were able to stand each other for all the time they've been through.
It wasn't until the turn of the 21st century, and the building/opening of the House of Mouse, that the two really started to develop their friendship further. Timothy got more chances to interact with Jiminy in a casual setting when both of them would otherwise be busy. They still argued a bit, but Jiminy and Timothy became a duo of sorts, always looking out for the other and consoling each other when they had troubles. (Oddly enough, it was Timothy that mainly saved Jiminy from being eaten by Timon and Jiminy that kept Timothy out of any major fights.)
As time went on, Timothy started to develop odd feelings for Jiminy that even he couldn't explain. He kept the thoughts to himself, mainly because he didn't know how his friend of over seventy years would react. That all changed when the Disney company seemed to be going through a dry period, and both sidekicks felt underappreciated. They ended up going to a bar to break a long-held soberity and ended up getting drunk out of their minds, which led to them "confessing" their feelings to each other.
The next morning, both of them woke up at Jiminy's place in bed together. It didn't take much to figure out what had happened the previous night; one look at the clothes strewn around the room was enough to put two and two together.
After that, Timothy and Jiminy went through a period of not talking to each other. Each of them felt guilty about what had happened and had decided that it'd be best if they didn't see each other as often as they used to. But as the weeks went on, the mouse slipped into a lovesick depression. He ended up talking to the Evening Star one night, wishing that there was some way for him and Jiminy to patch things up because he missed the times that they had together.
That night, the Blue Fairy visited each of them separately while they sleeped and promised to make Timothy's wish come true. Using her magic, she took the situation into her own hands and created a little girl, part-mouse and part-cricket, filled with joy and wonder. The fairy dubbed the newly created child "Heather Jane" and sent her off to awake her new parents the next morning.
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Heather adores her two fathers and aspires to be at least somewhat like each of them. (adding more later)
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