Angelii Essay
Six has always been a bit of a recluse, so it's not immediately obvious what sort of changes he's gone through. In fact, most of his time in Nautilus is currently divided as it had been since his arrival: training, patrolling, and keeping Dr. Rebecca Holiday from burning her own house down. It's rare for Six to spend much time away from this self-set routine of his.
When he first arrived in Nautilus, he trusted no one except Holiday and Rex Salazar who both came from his world and whom he felt the need to protect despite them being more experienced in this strange new world where willpower could directly affect the physical world. He largely regarded the city as enemy territory with a possible threat lurking around every corner. This was heightened when he was told about Unmaking. It wasn't his own loss to the multiverse he was concerned with but that of Holiday and Rex. Six saw himself as an easily-replaceable soldier, but their world needed those two so badly to give hope that one day a permanent cure to the EVO epidemic would be found. To ensure their safety, he started patrolling about the city, keeping an eye on things and getting a better idea of the lay of the land. Simultaneously, he kept tabs on the Network, largely remaining mute aside from the occasional post Nautilus saw fit to use to introduce him to his fellow citizens.
However, his blanket of protection slowly started to spread. There were people here that were important to Rex and Holiday, so he therefore felt compelled to keep those people safe as well. Starting with the Shadow reality storm, he started looking beyond just those he was personally close to and the ones they were close to. During that particular storm, he didn't even know Edward Elric yet had still gone out into the fog to help get the kid to safety. This might seem like a small matter to most, but for Six this was a huge leap forward: reaching out a hand to help other Wakened without being prompted with anything more than a need for help. After all, most of his adult life he'd been a mercenary who used others to achieve his own goals; even taking in Rex back at Providence had been so he could use the boy to cure his mentor. Simply helping someone because they needed help with no ulterior motive or hidden obligation was a huge break from the norm for him.
He started taking a more active part in Nautilus life, particularly during crises, such as posting a notice about the food spoiling problem when the Dark Aeon had kidnapped the lesser Wakened. He even started going to retrieve lost newly-Wakened, leading them to those more experienced who could explain things better than he could. He even performed this duty twice on the same day. One of them was Rialynn Kollman whom he'd taken to the Northern welcome house and later saved from Drift when the Cybertronian mistook her for an enemy. The other was a lioness named Kiara whom he'd led to her mate Kovu who'd already been in Nautilus at the time.
Thanks to all that, Six started building connections with others even if they initially had no connection whatsoever to Holiday or Rex. With some gentle nudging from Holiday, he even adopted a second "son" in Xavier Martez, and the later loss of the teenager to Sleep hurt him deeply even though he wouldn't show it.
As another step forward, he even started to trust these other people more. For example, thanks to the Dark Aeon, he gained a respect and trust for Drift. In fact, he ended up giving Drift the highest form of respect he had: Trusting him to watch his back and even trusting Drift to kill him should he change into an incurable and un-containable rampaging EVO.
It wasn't until after a visit home in which he believed he'd died that he'd started not simply reaching out to help his fellow Nautilus citizens but to also reaching out for help. He wanted to get stronger to protect those he cared for, so he reached out to Raye Hino for extra Bending training when she offered it. He also reached out to Reverend William Jesse Grant to soothe his lingering troubled thoughts over what he'd believed was his permanent demise.
To those he was closest to, he started trying to open up more, particularly to Rex. The actions of his Shadow in particular had shown a fraction of who he was behind that stoic facade. He started talking more personally with Rex, trusting the young man he saw as a son with some of his secrets, yet another giant leap for him.
When his memories were changed to an alternate version of himself, he was in essence changed into one of the "monsters" his Shadow self had claimed lurked inside of him: a selfish creature so driven by desperation to see someone they cared for again that they were willing to sacrifice others to achieve that goal. He'd even killed Holiday and forced Rex to kill him to put an end to his madness. It had forced him to see just how precarious a path he'd chosen for himself was and how easy it would be to fall from it. Because he couldn't condemn his actions while under the storm's effects, it took him a week to get up the nerve to properly apologize to Holiday. It also changed his own personal mission a bit: Protect those he cared for from threats whether they be from the outside or himself.
Of course, he still has a long way to go. Old habit makes him retreat when things get too personal and he's not the easiest man in the world to talk to in the first place, but the fact that he's letting people in at all is a major change for him. He's taking the initiative to improve himself and learn to trust a little more by taking one day at a time.