My zombie apocalypse Irish Lads AU, I deemed "Survival Lads" just now, and more about it under the cut
TW for what you'd expect in an AU of this nature: death, suicidal ideation, you get the gist.
Brian and Daithi met in unideal circumstances: when the outbreak first started, Brian struggled alone to survive, looking so disheveled that Daithi mistook him as a dead thing, and shot him long distance with his crossbow. When he noticed an unusual reaction to the shot that wasn't characteristic of something dead, that's when he finally realized he had shot a guy. He rushed him back to his group (consisting of Evan, Jonathan, Tyler, and Moo) where they would reluctantly treat him and take him in, however losing Brian's right eye in the process. This group eventually led itself to ruin, leaving Brian and Daithi.
Daniel, by the time he had "founded" the group of survival lads, had seen so much death and immorality that he became cold, and careful, and a smile would be a rare thing. He had belonged to a much bigger group when it all started, but learned the hard way that the more people in the group, the harder it is to keep everyone alive. Through thick and thin, he could always count on his best friend, Wilbur, until he died in circumstances that Daniel couldn't help, leaving him broken and alone for quite some time, before running into Daithi and Brian. When Kevin and Seán stumbled into them, he was originally unaccepting of the two joining the small group, but ultimately grew attached to Kevin's unfaltering optimism and Seán's energy, traits he unknowingly missed of people he used to know, and a stark contrast to Brian and Daithi's dispositions. He would find himself becoming incredibly protective of Kevin, all the while keeping him a far enough distance away as to not get attached (although he already is), as he did not want to lose him, just as he lost Wilbur.
Kevin and Seán were best friends before the outbreak began, and they stuck together through it all. They always had a way about things, and they would drift seamlessly through groups of survivors, with at least drama as possible. They got extremely good at a routine of Kevin supply running and Seán having his back as he did so. They trust each other with their feelings and their problems, although neither one of them are necessarily any good at dealing with them. When they ran into the group under tight and life-threatening circumstances for the 5, they originally had no plans on sticking around. But as the group's dynamic worked out well in a tight situation, and Kevin needed rest from his ailments, they would end up staying. Daniel's rough disposition concerned them equally, and Seán was incredibly worried that he would end up breaking, always viewing Dan as someone who was entirely self-preserving, whereas Kevin simply worried for the guy, and made it a personal mission to make him smile as much as he could. Daithi and Kevin would have a petty rivalry at almost all times, although it was much more lighthearted on Kevin's end, Daithi disagreed with Kevin's optimism, and never thought much of him, deeming him to be uncapable of survival due to how goofy he is.
There are very strong points in this group and how they work: Daithi being the one who would volunteer for lookout most times, dawning his crossbow, Brian would hunt with him sometimes, and other times, he would be on standby. Daniel always had a plan, whether it worked out or not, he always had their best interest in mind, trying to avoid as many problems (and losses) as possible, at all times. And of course, Kevin and Seán already had their supply running tactics, that would aid the group where the 3 were originally lacking, and of course, they would attempt to bring smiles to them.
However, there are extremely weak points as well: Brian always slightly resented Daithi for saving his life when he had shot him, wishing he had just passed, instead of having to "suffer more in this shit". As well as this, Brian saw very little value in people's lives, and wouldn't hesitate to kill others who were bit or about to turn, or even people who just get in the way. Daithi's anger issues would show to be a frequent issue, and he would always have a problem with how the group does things. Whether it would be disagreeing with how reckless Brian is, how calculating and quiet Daniel is, or how optimistic Kevin and Seán are. Daniel liked to boss around the group, not for the power, but so he could assure himself that everything was stable and everyone is fine. Most of the group would hate this at times. Seán suspected Daniel was simply keeping them alive for his own benefit, or to avoid the same pains he went through previously, in the little bits of Dan's past that he has heard of. Of course, Kevin would always brush this aside, and of course his best friend would listen. Seán's morality is incredibly strong, and he refuses to kill anything that isn't dead, causing problems when not-so-friendly people get involved, as he would always trust the good of humanity.
You know, it's a wonder anything worse hasn't happened to them.
Thanks to @bifamiliarbrindley for chatting to me about the AU that I literally came up on the spot and that I'm now lowkey obsessed with.