Hammerhandle's Death Maul

A magical item from the Elderdays, Hammerhandle's Death Maul is a creation of Jorduldiam Fenoin, an Ardon Artificer who desired for nothing more than the exponential expansion of bloodlust.   Hammerhandle's Death Maul cannot be attuned or controlled by any creature.   If any creature attacks or takes an action against another creature (spell attack, melee attack, ranged attack, magic item activation etc) within 120" of Hammerhandle's Death Maul:  

1. the creature attacked may use a reaction (even if its initiative account has not occurred) to respond
2. the response includes an attack of opportunity against the aggressor or any other creature within 120"
3. the attack role used is either the creature that initiated the attack or the creature that was attacked (whichever is the higher)
4. an attacker against the creature that attacked or took an action, is made with disadvantage, but is made as normal against all other creatures
5. the attack of opportunity ignores distance and is based off a melee weapon possessed by the attacker, and the attack counts as magical for the response.
6. any creature attacked this way, can of course respond starting with step one

Each consecutive round that Hammerhandle's Death Maul is active, the area of effect expands by 30", to a maximum of 360".   For each two rounds where no attacks or actions are taekn against anohter the area of effect reduces by 30" to the 120" minimum.