Some things to consider:
Simba: He barely escaped the Elephant Graveyard with his life and nearly cried when he learned how disappointed Mufasa was in him. Only a tiny cub, Simba was also forced to flee for his life both during the stampede and after, fully convinced that he had murdered his father. He was chased by hyenas through a gorge, down a cliff, through sharp thorns, and finally collapsed of heat and exhaustion in the desert where he was almost consumed by vultures. For the rest of his life (until Nala discovered him, that is) he had to live with the horrible "fact" that he had killed Mufasa and abandoned his pride.
Mufasa: He suffered a painful and horrifying death when he was betrayed by his own brother and thrown into a gorge where he was crushed to death beneath the hooves of some terrified wildebeest. In a way Mufasa also felt "betrayed" and disappointed in Simba when he learned that the young cub had disobeyed his orders to stay away from the Elephant Graveyard, and of course terrified for his son's life both in the Graveyard and the gorge.
Scar: He initially never even had a chance to be king, something he'd been longing for all his life. When he finally did usurp the throne, Simba showed up to rightfully reclaim his kingdom. After fighting a fierce battle with the young lion, Scar was thrown down a cliff and eaten alive by the very hyenas he had considered his most loyal supporters.
Sarabi: She lost the two most dear members of her family, her mate and son, in one shocking day. When Scar took over, the aging queen could do nothing but stand by and watch as her Pridelands crumbled before her. During Scar's reign, there was almost no food and she was constantly subjected to the ridicule of the hyenas. Finally, towards the end of the film, Sarabi was slapped so hard it knocked her to the ground.
Nala: As a young cub, Nala lost her best friend in the tragedy in the gorge, as well as the king she looked so much up to. Growing up, she was given very little food and had to endure Scar's continuous advances.
Lol okay you didn't really have to read all that as it was kind of inflated, but just tell me what you think. ^^ I won't tell you which one I voted for yet... I'd like to hear your opinions first.

I had to restrain myself from including Banana Beak in this poll because I want it to be strictly for lions.
