1. They both have fluffy, light-colored hair.
2. They are both royalty. Mytho is a prince, Nia is a princess.
3. They are both spawned from villains. Mytho comes from Drosselmyer's story. Nia is the daughter of the Helix King, Lord Genome.
4. They both start out clueless about certain fundamental concepts. In Mytho's case, it's because he has lost his heart. In Nia's case, it's because she has been sheltered all her life.
5. Mytho attacks with pink flower petals. Nia has pink flower petals in her EYES.
6. By nature, they are both sweet and innocent.
7. As a result, they are loved by nearly everyone they come across.