Because you like Sam Vimes in Discworld
It's easy for Brian O'Conner to fake his way into the world of extreme racing because he's been popping cars since his teenage years. See them in The Fast and the Furious.
Dominic Toretto lives his life "a quarter mile at a time", and he burns through those miles faster than anyone. See them in The Fast and the Furious.
Whether he’s hacking or dodging a bullet, Neo has a poker face that never drops. And it doesn’t hurt that he’s prophesied to be "The One" to save humanity. See them in The Matrix.
Poison Ivy is a seductive, venomous botanist laments the fact that there are so many people to kill, yet so little time. See them in DC Extended Universe.
Brilliant, violent, and only a little insane, the Joker doesn't listen to anyone except the voices in his head. See them in DC Extended Universe.
Aang is already a master airbender and once he learns to manipulate water, earth, and fire, he'll be truly unbeatable. See them in Avatar: The Last Airbender.
Eren Jaeger will erase the Titans from this world until not a single one remains. See them in Attack on Titan.
An aloof punk rock goddess, Nana Osaki has a surprisingly big heart. See them in Nana.
Once a lonely hat maker, Sophie Hatter is now cleaning goo from bathtubs and cooking breakfast for the grumpiest wizard in all the land. See them in Howl's Moving Castle.
Steven Universe is an excitable youth who likes junk food and trying to save the world. See them in Steven Universe.