“you, inej. you.”

Reason 1: from a game play standpoint, you only get a few optional missions. Those missions are helping Mary when she asks (who is Arthur's like, old girlfriend/ex/situationship/it's complicated) and CHARLES when he asks Arthur to help with the local Native American tribe

Reason 2: Charles is super introverted, and doesn't talk to other gang members much at all. However, when Charles goes bison hunting, despite it being a sacred thing that he holds really close, he invites Arthur along

Reason 3: John, Arthur's sort of brother, gets SHOT and MAULED BY WOLVES and Arthur makes fun of him and doesn't treat it seriously. But when Charles burns his hand, Arthur is super doting on him

Reason 4: Arthur doesn't hug people very often, and when he does its always because another person initiates it. He doesn't go in for the hug himself. EXCEPT. With CHARLES. And they hug not once but twice. Once when Arthur finds out that Charles isn't dead, and again when Charles leaves the gang

Reason 4.5: when they hug the last time, you can see them hold hands for about two seconds once the hug has finished, as if they don't want to let go yet. (Which they probably don't because Charles knows that this is probably the last time that he'll see Arthur)

Reason 5: when Mary (again, Arthur's weird ex girlfriend/it's complicated) asks Arthur to run away from the gang and live with her, he says he can't because the gang is his family and he has to stay loyal to Dutch (who is Arthur's father figure/leader of the gang) but when Charles says he's staying to help the Native Americans, Arthur is immediately like "Okay I'll stay too" ............ yeah okay buddy those are totally straight tendencies

Reason 6: Charles is one of the few people that actually shows compassion, care, and offers Arthur a sort of solution when he tells Charles that he's dying. He also says "Oh Arthur" and it's the most devastating thing ever

Reason 7: Charles doesn't make fun of Arthur like. Ever. everyone else calls him stupid and not worth much else than basically a work horse. There are two times when Charles does say it but the first time is when Arthur makes a joke and he goes "you simple minded fool" but like. In a silly way. And the other time Arthur is being Problematic and Charles goes "I know you're not as tough and dense as all that"

Reason 8: Charles goes back for Arthur, finds his body, and buries him. And his grave isn't just the regular tombstone that anyone else's is. It's hand carved wood, on a mountain overlooking the morning sun because "That's what he would have wanted". And there's also flowers purposefully grown there as well

Reason 9: Arthur isn't often given a choice in who he gets to take on missions but when he does, it's always Charles.

Reason 10: Arthur is weirdly submissive towards Charles? Not in a sexual way, but he won't take orders from anyone else besides Dutch and Hosea, and then also Charles.