This bow doesn't require amunition. Magical arrows you want to use magically teleport from any space of your equipement onto your bowstring.
Once per turn you can deal additional 1d8 lightning damage as part of your attack. The target recieves this damage regardless of wheather you hit or miss.
Mistbond
If you carry this artifact with yourself for 3 days, it becomes bonded to you. Once it becomes bonded you can summon and dismiss it at will. The bond is broken on your death or if you spend 30 seconds to break it.
Cloud travel.
You can travel through overcast for a distance up to 30 kilometers. To do this, as an action shoot an arrow into the clouds. You instantly become aware of any space below the same cloud or cloud cluster in a radius of up to 30 kilometers. Choose any place directly below the cloud and instantly teleport there. The whole process takes 6 seconds. You can use this feature a number of times equal to your wisdom modifier per long rest.
Call lightning.
As an action you can shoot the target and simultanously cast call lightning spell on your target. The target still recieves normal attack damage and also becomes a target for call lightning spell. You can concentrate on a spell to use it on each of your turns for the next 10 turns, as with normally cast call lightning spell. You have to triger it identically each turn, for the concentration to not be broken.