I´m debating between Eris and Cayde, both of them have quite the personalities, specially Cayde In the case of Eris, just imagine the way she sees things, she is already between light and darkness, but she isn´t in the awoken category, Morn has been through the darkness as a guardian of light and rose from the pits of the hive hellmouth as another person, we barely have knowledge of the things she had to do to survive, but there are still things yet to be discovered. Cayde is like a coin, we have the sarcastic, comedy filled and charming exo, but the other side of the coin has many mysteries of the vanguard hunter, we know he has stuff hidden from the other guardians, and yet he focus on the well being of his people, take for example the grimoire card where he and a fallen captain (correct me if I´m wrong) ignored their rivalry and worked together to survive against the hive, there were no factions or wars, just the instinct of survival. Those are my votes.