A stereotypical combination of Dwarven crafting and magical modification, these blades are known to present themselves to those with a knack for dexterous, quick fighting. Appearing as a steampunk quiver, this contraption is actually carried as a duffel bag/hip sling, being slung over the wearer's opposite shoulder. It magically fastens itself to the wearer's side comfortably, and its strap size can be adjusted to the wearer's discretion. It is open at one end, and looking inside, a total of five docked shuriken-like blades can be seen. 

To use: At the start of your first combat turn as a bonus action, one shouts a command word of choice, causing the Wondrous Self-Guiding Blade Wheel Launcher to let out a fat puff of cotton candy-scented steam with a hiss, which prepares it for use. This gives disadvantages made on stealth checks that turn. Next, on the turn the wearer chooses to use the device, the wearer chooses how many blades they want to release, up to a maximum of five by pressing a color-changing LED button on the side of the Wondrous Self-Guiding Blade Wheel Launcher the corresponding number of times. For the number of blades chosen, the wearer takes damage equivalent of the number of blades multiplied by their class level as a needle pierces their side to draw blood which is used as fuel. The blades then fly out of the open end of the device, at considerable speed towards any combination/number of up to five enemies (target all to one enemy, the total number of released blades to one per enemy, or anywhere in between). This counts as one standard action. After the attack, the wearer must wait 2 turns for the blades to both return and the device to cool down after such a high-power launch. The blades return in an upward-backwards arc toward the user, rising 5 feet over the target in the process.

Attacking Logistics: Hit is 1d10+ 1/2 of Strength score ( b/c blood thing). The creature being attacks must make a Dexterity saving throw equal to 15+ Dex Modifier for each blade, or take (number of blades)d6 piercing damage. The damage is halved on a successful saving throw.

Conditions: 

a) If the DM deems the blades to be obstructed in their return path, the obstructed blade(s) take an additional turn to use whatever magic they were imbued with to either find a new route to return, or overpower whatever holds them down, with a limit of anything above a large creature, or an object weighing over 350 pounds. If the blades are permanently obstructed by either a crippling weight or an indestructible object, they stop trying to come back, and can be used as normal daggers. But, if these daggers are thrown at the wearer, they will be sucked back into the device without harming the wearer.

b) If the wearer has had their health healed or increased in any way by magic, that health is removed first, and the blade(s') damage is increased to 1d8 per blade.

c) If the wearer is poisoned, then the blade(s') damage is reduced to 1d4 per blade.

d) Once used in a battle, the device must take a day to clean itself, or the wearer can take one hour to clean it manually, and perc/int/wis/ins/rel checks can still be made on objects within 10 feet of the wearer while cleaning. The wearer can still communicate while cleaning the device as well, but any other actions such as moving or casting concentration/movement requisite spells cannot be performed.

The boomerang is a ranged weapon, and any creature proficient with the javelin is also proficient with this weapon.

On a miss, a boomerang returns to the thrower's hand.

Notes: Damage: Piercing, The user puts on the Wondrous Self-Guiding Blade Wheel Launcher, Range