Atticus and Zane are likely characters created within the fanfiction world. They could be friends, colleagues, or even rivals. Without more context from the actual fanfiction, it's hard to say exactly who they are. But they are the main characters involved in this shaving - related situation.
They could be part of a specific group or community within the fanfiction. For example, they could be members of a club or a team. Atticus could be the more responsible one in the group, and Zane could be the wild card. Their relationship is such that Atticus feels the need to get Zane to shave, which could have implications for the group dynamic as a whole.
Atticus might be a character who is more of a caretaker or an advisor type. He sees something in Zane that makes him think shaving is a good idea. Zane, on the other hand, could be a character who is a bit stubborn or set in his ways. Maybe he's a rebel type who doesn't like to conform, and Atticus has the challenge of getting him to shave.