Shakujo of the Drowned Spirit

Staff (Divine or Druidic focus), Legendary, Requires Attunement by a Cleric or Druid

“The Shakujo of the Drowned Spirit is an odd religious artifact originating from the Islands of the Eastern Seas. It looks to have been an oar that was damaged in a shipwreck that has been repaired by the addition of, now rusted, iron reinforcements that depict swirling wave patterns, and hold several heavy iron rings.

Those who have been around its wielders have reported an eerie feeling that emanates from the artifact, its heavy rings clanging out as you go.”

This staff can be wielded as a magic quarterstaff that grants a +2 bonus to attack and 

damage rolls made with it. Additionally, when making an attack with this weapon, you may extend its Reach out to 30 ft. by calling upon powerful winds to buffet your target, rather than the staff itself. 

One With the Waves - You gain a +2 bonus to your Spell Attack and Spell Save DC when casting a spell that controls wind or water. (I.E. Tidal Wave, Wind Wall, etc…)

Dark Harbinger - As a Bonus Action, or upon using any of the following features from the staff, your appearance becomes that of a featureless humanoid shadow with white, softly glowing, eyes. While in this form, you gain a Flying (Hover) speed equal to half your normal movement speed, do not need to breathe, and add your Spellcasting modifier to any Concentration checks you make. You remain in this form for 1 minute and cannot end it early. Activating another ability of the staff or using subsequent Bonus Actions extends the time by an additional minute.

Endless Sea - As an Action, you can create up to 20 gallons of seawater within range in an open container. Alternatively, the water falls as rain in a 30-foot Cube within range, extinguishing exposed flames there.

Watery Grave - As an Action, you may cast the spell Watery Sphere. When cast this way, a creature Restrained by the sphere automatically begins Suffocating, as the water attempts to force its way into the creature’s lungs. You can cast this spell in this way once per Long Rest without expending a spell slot or by spending a level 4 or higher spell slot.  

Raging Seas - As an Action, you may cast the spell Control Weather, but may only do so at sea or in coastal areas. When cast in this way, the time for changing conditions is measured in Rounds rather than Minutes. You can cast this spell in this way once per Long Rest without expending a spell slot or by spending a level 8 or higher spell slot.  

Curse - This staff is cursed. If you die while attuned to this staff, your soul is corrupted and transformed into an Umibozu, a shadowy spirit of vengeance. While your soul is in this form, you cannot be revived by any form of magic and the curse on your soul can only be ended by a Wish spell. 

Upon dying, your body explodes in a massive storm of wind and water, causing four instances of the Tsunami spell (Save DC 18) to originate from your body which travel in the four cardinal directions. Additionally, a massive storm, forming in a 5 mile radius overhead begins immediately, causing heavy rain, gale force winds, and violent lightning. This storm lasts for 1 week, after which it dissipates.