Definitely Oliver Queen. He's at the center of so much in the Arrow series, and when it comes to the Mirakuru, his battles against those who have been affected by it are prime material for fanfic. Slade Wilson is a must - mention too. His fall from being Oliver's ally to a formidable enemy because of the Mirakuru is a rich area for storytelling. And Roy Harper. He was one of the characters who had to deal with the Mirakuru in his system, and his struggle to control it and be a hero despite it all makes him a popular choice in fanfic.
Oliver Queen is often a popular character in Arrow Mirakuru fanfic. Since he's the main character in Arrow, many fanfics revolve around his interactions with the Mirakuru - enhanced foes or allies. Slade Wilson is also very popular. His transformation due to the Mirakuru makes him a complex and interesting character to write about. Another one is Thea Queen. Writers might explore how she reacts to the Mirakuru - related events in the Arrow universe.
Oliver Queen, no doubt. His journey as the Arrow and his encounters with the Mirakuru - influenced villains are often explored in fanfic. Slade Wilson is also highly popular. His character arc, which is deeply intertwined with the Mirakuru, is fascinating to many fanfic writers. Additionally, Sara Lance can be a popular character in Arrow Mirakuru fanfic. She has her own storylines that can intersect with the Mirakuru - related events, and her skills and relationships can be further developed in fanfic in relation to the Mirakuru.
If you want the clearest chapter reference, go to Chapter 127. Early on, Witnessing Jiang Li leave with a bucket, Jiang Yan refused to admit...; later, the chapter leans on Otherwise, how would he ever show his face in the Capital again?"....
A practical answer is Chapter 72, because it turns the idea into a concrete scene. The chapter opens with Jiang Yan was still griping when suddenly a fair hand reached out beside..., adds pressure through [HAHAHAHAHAHA, this is the first time I've seen Director Sun speechless.]..., and ends on.
The best chapter pointer here is Chapter 100, "Ominous, there might be a bloody disaster!". It opens with The barrage was about to die of laughter. and closes on Her eyes flickered slightly as she grabbed the hand..
If you want the clearest chapter reference, go to Chapter 102. Early on, When the camera cut back, the three of them had already returned to the...; later, the chapter leans on The mud on Jiang Yan's body had dried mostly from the wind, and he walked....
Chapter 106 is the strongest chapter-level answer because it starts from Thinking of this, He Yun nodded with a hint of anticipation. and follows through on Jiang Li's fingers lingered over the three copper coins, her clear voice....
Look to Chapter 72 for the clearest answer. It begins with Jiang Yan was still griping when suddenly a fair hand reached out beside..., keeps building through I'll take these, thank you." In an instant, five pairs of eyes stared over..., and lands on Think about it." Jiang Yan fell silent..
If you want the clearest chapter reference, go to Chapter 98. Early on, Jiang Li listened to the end and didn't have much of a reaction, only...; later, the chapter leans on Each script is more far-fetched than the next.] [Exactly, doesn't anyone....
Look to Chapter 112 for the clearest answer. It begins with These five people are supposed to be at odds., keeps building through When did they become so in sync?] [I'm dying of laughter hahaha why is..., and lands on [Hahahaha why is the Princess starting to look disappointed?] [Help, even....
Look to Chapter 104 for the clearest answer. It begins with Zhao Lang let out a light chuckle, "Young Master Jiang, don't be nervous,..., keeps building through You're Daddy's guests, how could I possibly come to settle scores with..., and lands on Despite a whole day's labor, his face was.
If you want the clearest chapter reference, go to Chapter 60. Early on, What's with Jiang Yan, treating his own sister Jiang Li like this?" "He...; later, the chapter leans on When Jiang Li found a place to live, she didn't bother with him either,....