Issei sees Michael as a very powerful leader and respects him very much. Likewise, Michael has shown a great liking towards Issei due to his kindness and power. Michael gave Issei Ascalon as a symbol of peace between the Three Factions prior to the events of the Kuoh Treaty.
Michael has become the spiritual support for Irina ever since she found out that God died. He is also her leader as she is one of 'his' Brave Saints.
Michael and Azazel have an intense rivalry with one another. In the past, Michael once revealed Azazel's Artificial Sacred Gear's design throughout the entire Heaven, a fact that Azazel still holds a deep grudge on.But still after the peace treaty that alliance made they have seen cooperating each other despite of their intense grudge to each other.
Michael and Gabriel are shown to be get along well to each other because of their status as brother/sister. She greatly respects her brother as leader of the Heaven.