The War Master allows you to purchase resources with many different currencies that you can find in your adventures. There are different sections in the shop once you unlocked the respective feature. All sections have different refresh rates when their inventory will refill. Make sure to visit the War Master frequently.

Arena Shop

Use arena tokens to buy goods in the arena shop.

Guild Shop

Once you have collected guild tokens from guild quests, you can spend them at the War Master.

You can navigate to the War Master by clicking on the bottom right corner of the guild's main menu.

You can buy various rewards, from gold to reincarnation stones, among others. As the guild level increases, enhanced rewards become available in the guild shop.