Again, if we correct it to be about 'Game of Thrones'. Sansa's character development is crucial. It shows how a person can transform from a vulnerable and idealistic child to a shrewd and powerful woman. Her experiences shape her. For example, her time with the Boltons made her more resilient and less trusting, which are important traits for her survival and rise in the power structure.
In terms of character development in Sansa's story, it's a long and arduous journey. She has to overcome the trauma of her past, such as the abuse she suffered at the hands of Joffrey. This trauma could have broken her, but instead, it becomes a catalyst for her growth. She learns to be more calculating, to use her beauty and charm not just for attracting suitors but for political gain. She also develops a sense of loyalty and justice, which drives her to reclaim her family's honor and the North, which is a huge step in her character development.
Sansa's development in the story is a story of self - discovery. She discovers her own strength. Initially, she relied on others like her family and later, she realizes she has to fend for herself. This is evident when she starts to make her own political moves. She goes from being a damsel in distress to a key player in the power struggles of Westeros, and this development is what makes her character so interesting and important in the overall narrative.