Vegeta

Vegeta lands on Earth as the villain of the arc, kills his own partner for being disappointing, and leaves alive because Goku lets him. That decision shapes the next thirty years. He comes back as a rival, then a reluctant ally, then a resident, and he spends the entire time roughly one step behind a man he considers his inferior by birth. Being second is the wound the character is built around.

Vegeta's changing place in the story is easier to follow through his choices than his claims of superiority. At first he treats other fighters as obstacles or tools. Later he cooperates with people he once fought, even while insisting on his own superiority. His rivalry with Goku gives those changes a constant point of comparison: the same opponent can provoke resentment, competition and eventually respect.

For a puzzle solver, the useful distinction is between his name and his title. Prince describes his status among the Saiyans; Vegeta is the six-letter answer. Clues about Saiyan royalty, pride or Goku's rival point toward him. Goku's Saiyan name, Kakarot, is another name you may encounter in discussions of their rivalry, but it names Goku rather than Vegeta.