Wondrous item, rare (requires attunement)
This bronze crossguard is designed in the likeness of a pair of wings. You can spend an hour attaching the crossguard to a melee weapon, which can be done over the course of a short rest.
While a weapon has the crossguard attached to it, it gains the following properties; it gains these properties even if you aren't attuned to the crossguard:
If the weapon was nonmagical, it's considered to be magical and gains a +1 bonus to attack and damage rolls made with it.
It has the thrown property, with a normal range of 20 feet and a long range of 60 feet; if the weapon has the two-handed property, these ranges are halved.
If the weapon already has the thrown property, making a ranged attack with it at long range doesn't impose disadvantage on the attack roll.
If you're attuned to the crossguard, the weapon gains the following additional property.
Flyback. Whenever you make a ranged attack with the weapon, you can choose to have it fly back to your hand immediately after the attack hits or misses the target. Alternatively, if the weapon is within its normal throwing range from you, you can use a bonus action to speak the crossguard's command word. When you do, the weapon flies to your hand in a straight line. Any obstacle that provides total cover stops the flying weapon. Each creature in the weapon's path must succeed on a DC 13 Dexterity saving throw or take damage of the weapon's type equal to its damage die (you don't add your ability modifier to this damage). If you don't have a free hand, the weapon lands at your feet instead.
"The blade is nothing special."
"I saw it fly through the air back to you!"
"Oh, the blade is nothing special—the guard is worth more than all of our lives put together."