Oc is a 12 year old at the start who joins Fairy Tail to get off the streets, with a combination of holder and Caster magic. Over time he becomes the older brother and later father figure of all the children who begin to join the guild, first it was Laxus, then Cana, followed by, Levi, Bicklow, Ren(who still joins Blue Pegasus), Gray(who Oc had met during an encounter with Ur), Erza(who he notices has Dragon Blood of all things, providing her a large, and surprisingly stable magic container for her age),followed by Natsu, Wendy, Rogue, and Sting(tho he still watches over Gajeel, along with Juvia due to the Magic Council mistrust with Phantom handling children), tho he seems to know something about Dragon Slayer magic, to the point he can force the Slayers to stop using their magic with a simple glare in their direction, he also guides Erza into manifesting Dragon Fire to assist her requip.

He basically gets assigned to watch over children from the other legal guild due to the fact children aren't supposed to join guilds(its not a set law, more of a morals thing), so he visits the other guilds and watches over the children, and ends up either the older brother of the children, or the father figure many of them seem to need.

The Oc knows about Dragon Slayer magic due to being a Dragon Slayer himself, a fifth generation slayer, also referred to as a Dragon Eater, someone who gains their magic via Eating a Dragon. To circumvent becoming a dragon himself,, he used Takeover on the dragon seed developing inside him. He is a Dominance Dragon Slayer, a form of black dragon slayer magic pointed towards Dominance Dragons, a black dragon that forces its will on other and forces its Dominance on them, along with a Crimson Dragon Slayer, having been forces to fight a Crimson Dragon, and kill it, devouring it shortly after(not only gaining its magic, but its magical power as well)Fifth generation slayers don't suffer from motion sickness.

Dominance Dragon's Dominating Aura
Obedience Glare
Cancel Glare(cause magic to deactivate when glared at)

Crimson Dragon's Shining Wave

Irene learns of him preventing himself of turning into a dragon and confronts him, and is dumbfounded by the idea of using Takeover to remove the dragonseed, basically still becoming a dragon, but in a way that keeps him human, he got a dragon seed for both of his slayer magics, therego two dragon soul forms. And when she learns he's become a father figure for her daughter, she's basically become a stalker hes formulating a plan to make him hers, also Erza seems to always sense Irene and know she's familiar both to her magic signature and her scent.

Oc also gets Erza to tell him of the Tower of Heaven, and quickly confront the tower alone, utterly destroying the building, accidentally activating it incorrectly, reviving a Tidal Dragon as a soulless beast, kills it, eats it, gains its magic(spells) and magical power(the energy of its magic container), and proceeds to destroy the mind influence of Jellal with Cancel Glare, and take all the children back to the guild, before hunting down the person who casted the spell of Jellal in the first place, finding a little girl that reminds him of Ur, who turns out to be Ur's daughter, who Ur thought had died from having to much magic.

He also went to the Heartfillia mansion when he learned about the Dragon Slayer kids, and forces ethernano into Layla, keeping her from dying of magic deficiency syndrome.