5. Willow Rosenberg (Buffy The Vampire Slayer)
Buffy Summers, as the girl destined to stand alone against the demons, the vampires and the forces of evil, might seem like the obvious choice to pick for a Blue Lantern ring from the Buffyverse but, in my opinion, Willow Rosenberg is better suited. In Buffy's big final battle, the one that would define her against the First Evil and its forces, she was hopelessly out-gunned. But, thanks to the vast mystical powers at Willow's disposal, all of the girls who could potentially be slayers were turned in to slayers, giving Buffy the backup she required to put up a fight and, ultimately, win the battle and bring hope to the world. The fact that Willow had come through some very dark times, such as the death of Tara and her subsequent descent in to world-destroying recklessness, also exemplifies the fact that there is hope for everyone.