Maybe someone forced him to. For example, a friend who is a big Syrus fan might have put it on and made Zane stay and watch.
Perhaps he lost a bet to someone and the punishment was to watch Syrus fanfiction. So, he has no choice but to sit there and endure it, all the while thinking about how he can get out of this awkward and unplanned viewing situation.
He might be really bored or annoyed at first. Maybe he'll roll his eyes a lot and keep thinking about how he got into this situation.
It's quite normal. In a fandom, people are interested in different aspects of the characters. Zane might be curious about Syrus's backstory, relationships, or potential storylines that fanfiction writers have created. It's just another way of engaging with the fictional world they are part of.
It could mean that Zane is interested in Syrus's story as told in the fan - created fictional works. Maybe he wants to understand Syrus better through the different interpretations in the fanfiction.
Perhaps Zane is a big fan of Syrus himself and by reading the fanfiction, he gets to delve deeper into the Syrus - centric stories. It could also be that he enjoys the creativity of the fanfiction community and how they expand on the Syrus character in ways the original work might not have.
Maybe Zane and Syrus get trapped in a strange virtual world created by some glitch in the digital system. They have to rely on each other's skills to find a way out. Zane's logical thinking and Syrus's knowledge of the digital realm might be combined to overcome the various obstacles like malfunctioning programs and security barriers.
The main characters are clearly Zane and Syrus.
Zane might start by assessing the situation. If they're in a dangerous place, he'd be very cautious. He could also be a bit impatient with Syrus at times, but still try to keep him safe. For example, if they're in a dungeon - like area in the Duel Academy, Zane would quickly find a way out, pulling Syrus along if he has to.
At first, their relationship might become strained. Zane's anger could make Syrus confused and a bit scared. Syrus might try to avoid Zane, not knowing how to deal with his anger.
Another aspect of their brotherly love in fanfiction could be the way they support each other during tough times. Syrus might be having a hard time with his self - confidence, and Zane would be there to encourage him. He could tell Syrus about his own insecurities when he was younger and how he overcame them, thus inspiring Syrus to grow and believe in himself more.
There's no way to really say if it's common without knowing more about Zane. If he has a lot of free time and is a die - hard fan of the source material involving Syrus, then it might be a regular pastime for him. However, if he's not that into the whole fan culture or Syrus specifically, it would be less common.