Lion

Born from a loving mother but a neglectful, abusive father, Lion and his mother, Sand, were abused severely by Lion's father, Scar. They were packless, only living by themselves. Sand couldn't defend herself from Scar, but the best she could do was protect Lion. Scar manipulated them to stay with him in every way possible so he could continue the abuse. Sand and Lion had a bond stronger than any other; unbreakable. That was until Scar coldly murdered Sand when Lion was only 5 months old, leaving the poor wolf pup heartbroken and hurt.
Lion left that night and just barely escaped Scar's bloodthirsty claws. He was broken and hurt, bleeding from everywhere, with physical and mental scars that would stick with him throughout his life.
When he was just about to give up and let the world take him, some wolves found him. The Brokenclaw Pack. They took him in and he was adopted by the alpha at the time, Sun, who was a kind male wolf. Better than Scar. Almost as amazing as Sand. It took a while for Lion to open up to Sun, but gradually he did, and they had a strong bond. Even if Lion was bullied by the other adolescents for his small size and weakness, Sun always comforted him. Sun made him feel like he was worth something, unlike Scar, who constantly belittled him.
At 9 months old, Lion heard the worst news of his life. Sun was dying. He went to his dying father and stuck with him until his very last breath. After Sun's passing, Lion closed up again. He trusted no one. He continued on, bottling up his emotions, which caused him to lash out at random times of day. Lion had serious mental health issues.
Almost a year later, Lion was appointed Alpha of Brokenclaw Pack. He promised Sun later that night that he would be just as amazing as a leader as him. And he's stuck by that.