At battle start, sacrifice the X units in the SAME ROW below. For each sacrificed unit, +1 attack is given to all units; Gives +1 more if this unit shares a type with the unit that was sacrificed.
The sacrificed unit must share a type with the Blood Rage unit for the +1 more. Either all units will get the extra +1 or none will.
2 units have the Blood Rage ability: