Rin has the power of songs at her beck and call which makes her a formidable opponent. The One Above All has cosmic level abilities but he never tends to use them for combat and so he doesn’t have any spell to really take care of Rin. As a result she should have the advantage throughout the match to the point where he won’t really be able to do much of anything. He will be completely outmatched here from start to finish and is just out of options from the start. Rin (Lost Song) wins.