(For the purpose of this, Nimona doesn't come back at the end of the movie)
After the city had been rebuilt and Ballister and Ambrosious started rebuilding their relationship, they realized one thing, they felt like they were missing something. Bal chalked it up to having just lost Nimona. So they decided to go adopt a kid.
They met with a bunch, but only one stood out to them, you. Quiet, closed off, distant, it was clear something had happened before you were sent here, something you probably shouldn't have seen
Who better to help, then those two who understood you all too well
Ambrosious: and your sure you want this one? Ambrosious asked one final time, signing the paper work this won't be a walk in the park.
Ballaster: I know.. I'm sure he smiled at you gently