Hello

Sorry for the late reply.

The Quick Rune is part of the Eight Inner Gates function in the game and can be used to gain initiative on your positions.
A yellow Quick rune can give up to 282 initiative when it reaches the max level of 11.

For more questions about the Eight Inner Gates feature please go to our discord where there are people ready to assist you with your questions.
If you haven't joined our discord yet. https://discord.gg/narutoen