Final answer:
Mr. Darcy is the character who attended Lydia's wedding in 'Pride and Prejudice', surprising the other characters given his previous objections to Wickham.
Step-by-step explanation:
In the novel Pride and Prejudice by Jane Austen, the character who surprisingly attended Lydia's wedding is Mr. Darcy. Although he is not mentioned directly during the wedding scene, it is later revealed by Lydia herself that Mr. Darcy was present at her wedding to Mr. Wickham. This revelation is particularly unexpected given Mr. Darcy's previous objections to Wickham and his role in separating Wickham and Miss Bennet. The attendance of Mr. Darcy at the wedding showcases the depth of his character and his commitment to the Bennet family, especially to Elizabeth Bennet whom he deeply cares for. It's this act of quiet assistance that eventually leads to a shift in Elizabeth's feelings towards him.