FusionFall Headcanons: Runty
While many had their reservations about Billy's odd "pet," he's grown on a fair number of soldiers stationed at the Endsville base, becoming their unofficial mascot. Do your best to keep your eye on him though: There's no telling what trouble he may be involved in.
Being an imaginary friend, Runty is smarter than many people give him credit for. Unlike actual fusion monsters, he can talk, if in a very infantile way. He's more like the imaginary puppies in the FHFIF episode, "Who Let the Dogs In?" where instinct greatly overrides their limited intelligence. Signs of said intelligence include when he refers to the player as "Mama" or "Papa," likely as a result of Billy handing him over to us after the events of "Fuse No More (Part 2 of 4)." Considering that what followed was him getting sacrificed to weaken the shield in Fuse's Lair, this mission also served as an example of Runty's loving nature. with Billy noting how sweet he is and Runty seemingly forgiving us after these events.
Despite Runty continuing to stay by Billy's side after this, it's clear that he maintains some odd sense of affection for the player for the... few minutes at best, that he was passed over as their imaginary friend. He keeps pushing the title of "Mama" or "Papa" onto them, as if the player has some sort of co-parent status with Billy. It could also be a trait that he actually inherited from Billy, given the latter's sometimes misguided sense of compassion and regular habit of pushing his friendship onto others.
Sadly, like many of Billy's other pets, Runty is regularly the victim of neglect/abuse or unfortunate circumstances. Luckily for the little guy, since he was based on the malleable fusion spawns, he springs back from most injuries incredibly easily--ironically, another trait he also shares with Billy. Besides the incident at Fuse's Lair, Runty has been attacked by Milkshakes and fusion fighters, endured food poisoning, and run over by vehicles multiple times. Each time, he springs back without seeming any the wiser.
Since learning of his true origins as an imaginary friend, many people at the Endsville base have tried to see how they could put his ability to camouflage with actual fusion monsters to use. Runty has learned to follow some basic commands and repeat certain words he hears, and initially, there was some success in using him to maneuver around other groups of fusion monsters. However, the tactic wouldn't work forever. Eventually, either from realizing that they couldn't communicate with him through the fusion hivemind or paying attention to how he hung around the Endsville base, fusion monsters would recognize him as an enemy. Runty has ended serving as a distraction, bait, or placed in a kind of 'Lassie' role since. All in all, it wasn't a big loss since he really only listens to Billy or soldiers he's gotten close to for whatever the reason.
Runty's existence may have partially inspired Dexter to create the Unstable Nanos, being that they share much of the same traits and the same purpose for the war effort.
While typically sweet, Runty does have a couple of bad habits, those being "love bites" and trying to eat random objects. He's like a toddler that'll put anything in his mouth--one full of razor-sharp teeth that you definitely don't want to get your arm caught in.
