Well, revenge can also be seen as a theme in 'True Grit: The Classic Novel'. The protagonist is out to get revenge for a wrong done to her family. Also, the theme of self - discovery is there. Through her journey, the main character learns a lot about herself and her capabilities.
One main theme is the idea of perseverance. The characters show true grit as they face various difficulties. Another theme could be justice. They are on a quest that involves a sense of righting wrongs.
The themes in 'True Grit: The Classic Novel' are multi - faceted. There's the theme of moral integrity. The characters have to make decisions that test their moral fiber. The novel also explores the theme of loyalty. The characters form bonds and stay loyal to each other throughout their adventures. This loyalty is tested in different situations and is an important aspect of the story.