Because you like Kenny McCormick in South Park
Carl Fredricksen is a crotchety old man who may just have it in him to take one last, great adventure. See them in Up.
A gentle alchemist who is soul-bound to a giant suit of armor, Alphonse Elric is growing into the responsibility handed to him. See them in Fullmetal Alchemist.
Did he ever tell you the definition of insanity? Just wait, and this psychopath will do just that. See them in Far Cry 3.
Lady Macbeth takes being a powerful woman to a whole other level. See them in Macbeth.
Told her son will one day save the world, Sarah Connor dedicates her life to training him to do just that. See them in The Terminator.
Optimus Prime is a shapeshifting sentient robot leading a team of robots to stop evil from taking over. See them in Transformers.
It turns out the girl of your dreams just might have dreams of her own. See them in (500) Days of Summer.
Fiona Gallagher wants to be able to give her siblings everything that they deserve because her parents aren't going to do it. See them in Shameless.
Lady Bird's heart is in the right place, usually, but even the purest of people can fall sway to the havoc-wreaking traps of senior year. See them in Lady Bird.
