Return rune purpose and crash

I bought the return rune, (still don’t know what it does) and when I tried to use it I had the animation playing but nothing happened. I thought it was an attack so I charged up the spell once more and pressed X which resulted in my character performing the X rune skill. Then I charged up the spell once more and just moved my joystick. My character strated a movement with the sword (i use katana) and the game crashed, bringing me instantly back to windows.