It's hard to say without reading it, but it could be the strong female characters from the original 'Game of Thrones' like Arya Stark or Cersei Lannister. They are both complex characters with their own motives and arcs that could be further explored in a fanfic with an empowerment - themed title like this.
Perhaps it features a new character created by the fanfic author. However, if it sticks to the main storyline of 'Game of Thrones', it might focus on Jon Snow as he has a lot of potential for character development in relation to power and self - discovery. The 'hear me roar' aspect could be related to his journey to claim his rightful place and make his voice heard among the different factions in Westeros.
It could be about a female character in 'Game of Thrones' finding her strength and voice, 'hear me roar' often implies a sense of empowerment. Maybe it's a fanfic focused on a character like Daenerys Targaryen as she rises to power and makes her presence known in the cut - throat world of Westeros.
The underdog characters who start from a very low position but gradually rise to prominence. Their growth and development throughout the story, how they overcome obstacles and face challenges, make them really memorable in the 'hear me roar game of thrones fanfiction'.
One interesting storyline could be a female character rising to power in a way that defies the traditional male - dominated power structure in Westeros. For example, she might use her wits and charm to form alliances that no one expected.
There could be a young, ambitious knight who has seen the injustices in the Seven Kingdoms and becomes a key figure in the uprising. Another might be an old and wise maester who secretly supports the uprising and uses his knowledge to help the rebels. Also, a strong - willed noblewoman who has her own reasons for wanting change could be one of the main characters.
There's no way to know exactly without reading it. However, in a 'Game of Thrones' - themed fanfic with 'no mercy' in the title, it's likely to have some of the fan - favorite characters in key roles. Maybe Arya Stark, with her assassin skills, could be a main character, showing no mercy to those on her kill list. Or it could be Cersei Lannister, being even more merciless in her quest for power and revenge than she was in the original series.
I think Naruto would be like the central hero, similar to how Daenerys was in Game of Thrones. He wants to bring change and justice. Then there's Kakashi, who could be like a wise advisor, much like Tyrion Lannister in some ways. And Gaara, with his past of being an outcast, could be a character who rises above his circumstances, just like Theon Greyjoy did at some points.
There might be a Stark character as well, since in 'Game of Thrones' the Starks are often associated with wolves. They could be intertwined with the Black Wolf's story, perhaps as its protector or someone it protects.
The main characters could also be entirely new characters introduced in the fanfic. The author might create someone who has a unique connection to the events of the original series and is given the task of changing things. However, it's also possible that classic villains like Cersei could be main characters if the fanfic is about giving her a second chance at ruling, perhaps with a different approach this time.
There might be a new character introduced in the fanfic. This character could be a commoner who has a special connection with the dragon. For example, a shepherd who once saved the dragon when it was a hatchling and now the dragon has returned to repay the kindness. This character then gets involved in the high - stakes politics of Westeros because of their relationship with the dragon. Another main character could be a powerful lord or lady who sees the dragon's return as a threat to their power and will do anything to stop it or control it for their own gain.
There could be a fearless space captain as one of the main characters. He or she might be leading a group of rebels against a tyrannical interstellar regime, much like how some characters in 'Game of Thrones' fought against unjust rulers.