In the anime "Tokyo Revengers," the complexities of human emotions such as regret and longing are portrayed through the main character, Takemichi Hanagaki, as he navigates the intricacies of time travel to alter the past and prevent future regrets. Takemichi's deep sense of regret for not being able to save his loved ones and his longing to make things right drive the emotional depth of the series. The show highlights how these emotions can shape one's decisions and motivations, ultimately leading to a deeper exploration of the characters' inner struggles and growth throughout the storyline.