Yuki from The Melancholy of Haruhi Suzumiya. She is a humanoid/alien and has half personality (To attract attention of Haruhi).She always have to protect Kyon & she seems very lonely.Kyon is her only support ( If she considers him as support). If you have seen movie of Haruhi Suzumiya, you will understand her feelings.
Kagura from Ga-Rei: Zero definitely. She lost her mother at a young age and her father sent her away to someone else's house. She became best friends with Yomi after many years and then almost lost her. She watched Yomi in a coma for two months with injuries that made Yomi incapable of talking or moving anything but her head and hands. Then Yomi got possessed by the Death Stone and killed some of their friends and began fighting Kagura. Kagura then watched as her best friend fatally wounded her (Kagura's) father. Her dad then decides to tell her that he's always loved her and was proud before dying. Then Kagura is forced to kill Yomi the only thing important to her.... Talk about your living hell.
He was born with minimal talent and his chakra control...let's just say wasn't the best. All the kids made fun of him for his weakness and he trained to become stronger every night because of it. Rock Lee vowed to never give up.. He's one of my favourite characters. :)
I can say Izumi Rio (mostly from the manga of the series and not the anime). He killed himself when he was only six years old, only to make his mother happy, because she hated him from reminding her, his father. Also in the period before he commited suicide he was always beaten by his mom. Then he became a Shinigami as a punishmeant because of the fact he killed himself, but he did it all for his mother.. His whole childhood life was so sad.