To unlock a new level of combat mastery, in addition to completing various tasks you have to make an offering at the altar of Freyr, the warden of Alfheim. Access to Alfheim can be opened at the Challenge Arena at the foot of the Great Tree.

Not all items are suitable for offering, but only special ones that are made on the servant's table near the altar. There is a separate offering for each combat class - choose carefully!

To make offerings, you will need special rare resources. They can only be obtained after receiving the blessing of the combat masters' spirits.

Take Eternal Fire or Eternal Light from the Servant of Freyr in Alfheim and bring it to the statue of a combat master. Look for the statue, the weapon of which matches your chosen class.

A book with instructions near the altar will tell you in which locations the statues are located.