This is the main article 'about Mel and Lydia's relationship, a thief and a noble who hate each other', please help us write more closely about this relationship. You can look for dialog box in AV3 to write (the best way is to replay the game in easy mode).
Mel has a very unique relationship with Lydia. Mel, who hates nobles, and Lydia, who hates commoners, naturally share the same feeling of dislike and contempt with one another. Once the party meets Lydia to the entrance to Stormbend, they have a kind of verbal duel, concluding to them preparing to fight. The fight, however, was dismissed by Te'ijal, who approves of Lydia joining the group because she was a powerful mage.
They often quarrel in between major decisions. When in Pemberly Keep (and savoring their freedom from each other), they stay at opposite sides of the house. When Mel is the leader and is talking to Lydia inside the Keep, they have short banters, which irritates both.
When the player makes Edward propose to one of the girls other than Lydia (Mel or Stella), Lydia gets into a kind of fit, sometimes sulking angrily in her own, spacious room with all the gowns the player lets her have throughout the game.
Even though they obviously don't rub along perfectly, they disregard all animosities (or ignore them, for the moment) when in battle, or in major twists at their fate, such as Stella's sudden disappearance and Mel's kidnapping. I think Lydia doesn't have any nice things to ACTUALLY say about anyone especially Mel, who she thinks is a dirty rat. She only joined the quest to defeat Gyendal to keep an eye on Edward.