Galga and custas are both agile characters that end up performing in some way shape or form: Galga performs in the silver Eve festival opening with the Knight Moralis while Custas is a minstrel who has learned multiple dances and performed them with Dagda. However, both Galga and Custas end up with an injury that significantly impacts their place in society. Galga's injuries lead him to become an 'outsider/unknowing' as his memory is wiped by Ininia while Custas's injuries expose him to the knowledge of magic and make him a 'knowing'.
In some twisted way, Galga and Custas sustain their injuries when they are outside of uniform but are still trying to accomplish their 'duty'. Galga loses his memories, trying to do what HE BELIEVES is right by attacking Dagda, who had forbidden magic on him as well as rescue the children he believed were held hostage. On the other hand, Custas is injured when he tries to retrieve his and Dagda's belongings from the carriage because those belongings are their only viable economic lifeline as minstrels. Ironically, Custas and Galga are injured near bodies of water and are later rescued by witches: Galga is found by Atwert, and Custas is rescued by the efforts Qifrey's atelier.
While they're at a low point, Galga and Custas are found by Atwert and Tartah, who are keen on helping them. Atwert and Tartah aid Galga and Custas through teaching them: Atwert takes in Galga as an apprentice while Tartah teaches Custas about medicinal herbs and the alphabet. While Atwert successfully takes in Galga and is implied to teach him more about magic, Tartah expresses regret to Coco about not teaching Custas magic after he leaves with Dagda.
In their efforts to help the two, Atwert and Tartah experience the structural societal barriers reinforced by witch society. Reaching Custas magic is forbidden because he is an outsider. Restoring Galga's memories is forbidden because that is healing magic. Healing Custas's legs is also forbidden because that is healing magic. Atwert and Tartah are left with nearly nothing to help Galga and Custas directly, so they go about convoluted ways in doing so: Tartah teaches Custas what is permissable for him to learn and Atwert takes in Galga as an apprentice as a short term plan. Either way, both of them come to critique the laws in place, and Tartah breaks them in order to help Custas while Atwert is foreshadowed to also break them soon enough to help Galga.
However, it's important to note that even when Galga and Custas experience such dramatic character changes and progressions, a key part of them is still present. Galga still tries to help Ininia and saves her life even though she erased his memories (he isn't aware of this or of how the witches system works). Custas, while despising the pointed Caps and their ability to ignore his and Dagda's suffering by hiding information, still ends up offering knowledge and the pen to Jujy, who desperately wants to save Hieheart.
Both Atwert and Tartah choose to stay by Galga and Custas's side while also trying to seek more information on the predicament that they find themselves in. Something something Atwert commenting directly to the Knight moralis that Galga is "important to him" while Restys simply sees the situation unfold and comments to Tartah that "this boy is important to you, isn't he?" Not to mention that Adanlee is brought up for both duos: if it wasn't for Atwert's intervention Galga would be taken to Adanlee and if it wasn't for Tartah choosing to follow Custas and join the brimhats he would be sent to Adanlee for the spell branded on him.
Chapter 88 depicts the two duos next to one another side by side. Chapter 90 also reveals that Galwert don't go back to the Great Hall or a pointed cap predominant area as they choose to stay in Ezrest while Tartah and Custas abandon pointed cap society and become affiliated with a new society. This ultimately depicts how both of them have been pushed away from pointed cap society and are essentially 'outsiders' or misfits who don't fit in to the rigid system.
