Boon of Mastery (5e Epic Boon)
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Boon of Mastery
Once you have reached level 20 in a single class you may take this boon to gain a feature from a different subclass within the same class. When taking this boon you gain one feature from that subclass at the lowest level. This boon may be taken repeatedly to gain the remaining subclass features starting with the lowest leveled feature you do not currently have.
Example: A Totem Barbarian wants to take the first feature from the storm path so they take this boon and gain the first subclass feature. When taking the boon again they may take the next feature up the list or the first feature from a different subclass. However, since he or she is already a totem barbarian they may not take a new first level totem.