At player level 22 the feature Hero Sacred Gear is unlocked. Sacred Gear are possible rewards from summoning in Valhalla or they can be rewards from events. Equipping these on heroes improves the attributes of all heroes and when equipping the entire set it can unlock a set bonus for that specific hero.

The basic stats are an improvement that are given to all heroes when it is used. The Hidden Stats are given to all heroes if you also own that hero. This means that you can upgrade sacred gear for heroes you do not yet own, but you do not get the Hidden Stat bonus until you own it.

If you receive more than 1 of the same Sacred Gear you can use it to improve it, by clicking either the greyed out icon if you still need to unlock it or the yellow arrow next to the icon if you want to upgrade the item.

If you own the entire set and have upgraded them all the a specific rank they can unlock the set bonus. This bonus is specific for that hero and is not shared by all heroes.

This guide is sourced from yabusame.