The Sith Warrior's story can also be considered one of the best darkside stories in SWTOR. As a Sith Warrior, you are on a path of pure domination. You get to engage in epic battles, crush your enemies without mercy, and make choices that are deeply rooted in the darkside. For example, you can choose to sacrifice your own allies for more power, which is a very darkside - oriented action. There are also some great story arcs where you interact with other powerful Sith Lords and prove your worth through dark and often cruel means.
I'm not sure specifically as there could be many different 'darkside graphic novels'. Generally, it might be about dark themes such as mystery, horror, or the darker side of human nature. It could involve complex characters dealing with difficult situations in a dark and often gritty setting.
Tanjiro might use his sense of smell to detect hidden threats. Since his sense of smell is super - enhanced, he could sniff out any demons or traps in the way of saving Rengoku. For example, if there are demons disguised as allies, Tanjiro would be able to tell by their scent.
Since I don't know the specific 'darkside graphic novel', it's hard to say. But typically, there could be a brooding protagonist, perhaps someone with a troubled past. There might also be antagonists who represent the forces of the darkside more blatantly, like a powerful and malevolent villain.
Yes, in some fanfictions, Tanjiro is depicted as the reincarnation of Yoriichi. This concept adds an interesting layer to the story as Yoriichi was an extremely powerful and legendary figure in the original lore. The idea allows for new storylines where Tanjiro might inherit some of Yoriichi's skills or have a deeper connection to the past events related to Yoriichi.
Tanjiro's fate in the manga is that he ultimately passed away. This event was a significant part of the story's development and had a profound impact on the other characters and the overall plot.