Gaius took Merlin under his wing, but Kilgarrah pretty much did too. Because whenever Merlin was lost, not knowing what to do, and with no one else to give him answers in terms or magic, he would always go back to Kilgarrah. Just as he had learned from Gaius, he learned a lot from Kilgarrah, too.
Gaius taught him to use magic for good and not carelessly. Kilgarrah taught him how to solve certain magic situations and told him about his destiny, but he usually wanted for Merlin to solve things the cold and easy way. Which was to let someone die.
Merlin was always torn between what he had learned from the both of them.











