As an Action these axes can be combined into a single great axe or separated into 2 battle axes, each substituting the versatile property for the light property (meaning only 1d8 base damage).
When raging they deal an additional additional damage as indicated below:
Combined they deal an additional 1d8 radiant damage.
Individually one deals an additional 1d4 fire and the other 1d4 cold damage.
Proficiency with a Battleaxe allows you to add your proficiency bonus to the attack roll for any attack you make with it.
This weapon has the following mastery property. To use this property, you must have a feature that lets you use it.
Topple. If you hit a creature with this weapon, you can force the creature to make a Constitution saving throw (DC 8 plus the ability modifier used to make the attack roll and your Proficiency Bonus). On a failed save, the creature has the Prone condition.
Notes: Damage: Cold, Damage: Fire, Damage: Radiant, Requires attunement by a Barbarian or Fighter. When attuned these axes give of enough magic aura that they grant advantage on investigation, perception or arcana checks to determine their power., Damage, Combat, Versatile, Topple