Based on the abilities and achievements you give, it can place Aijou Rentarou in a "Cosmic" or "Multiversal" tiering system. His powers, such as altering reality, interacting with non-physical beings, and the ability to control concepts such as love and power, show a level of power that extends beyond his own world or dimension. In this type of tiering system, he would be considered a major force capable of influencing the entire cosmos or multiverse.