These magical instruments were designed by bards to showcase their skills in the arts while they are on the field of battle. Common instruments could be lutes with blades on the side to function as a lute and battleaxe, while rarer more powerful ones generally appear to look closer to instruments and less like weapons. The instruments are reinforced with magic so Bards using them in combat do not have to fear their breaking under normal circumstances.
A bard attuned with a battle instrument may use it as a focus for their spell-casting and utilize it as the weapon it is also created as. A Bard is considered Proficient in wielding a battle instrument if they are proficient with either it's instrument or weapon form.
A Bard uses their CHA for attack and damage instead of strength when deciding the attack and damage of an attack with a battle instrument, and the damage die associate is equivalent to their bardic performance die. The damage inflicted by a Battle Instrument is force regardless of what the real form would do as it is the talents of the bard dealing the 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: Requires Attunement by a Bard, Versatile, Topple