"Guardianship runs in the family. Also, anger issues."
I had a hard time finding concepts I liked for Berserker. This is inspired by Path of Ancestors. The value 1 Fury Die makes for a clear signal to use it for defense or movement (eventually can be rerolled by Furious Forebears).
Level 3
Ancestors’ Protection.
Whenever you or an ally within reach 4 Defends, after damage, gain a Fury Die of value 1.
Ancient Counsel.
(1/day) Grant yourself or an ally advantage on a Lore or Naturecraft check.
Level 7
Inherited My Old Man’s Mouth.
You always Taunt your adjacent enemies during their turns.
Level 11
Furious Forebears.
Whenever you or an ally within reach 4 gains any Wounds, reroll up to that many Fury Dice. Then, inflict that much necrotic damage to the attacking enemies, and they are Frightened of you this round.
Level 15
Guardian Inheritor.
(4/encounter) Apply That All You Got?! for an ally within reach 4.