Wave

Held in the dungeon of Temple of Sacred Storms, this Trident is an exquisite weapon engraved with images of waves, shells, and sea creatures. Although you must worship Melora to attune to this weapon, Wave happily accepts new converts.

Details
You gain a +3 bonus to Attack and Damage Rolls made with this Magic Weapon. If you score a critical hit with it, the target takes extra necrotic damage equal to half its hit point maximum.

The weapon also functions as a Trident of Fish Command and a weapon of warning. It can confer the benefit of a cap of Water Breathing while you hold it, and you can use it as a Cube of Force by choosing the effect, instead of pressing cube sides to select it.

Sentience
Wave is a sentient weapon of neutral alignment, with an Intelligence of 14, a Wisdom of 10, and a Charisma of 18. It has hearing and Darkvision out to a range of 120 feet.

The weapon communicates telepathically with its wielder and can speak, read, and understand Aquan. It can also speak with aquatic animals as if using a Speak with Animals spell, using telepathy to involve its wielder in the conversation.

Personality
When it grows restless, Wave has a habit of humming tunes that vary from sea chanteys to sacred hymns of Melora.

Wave zealously desires to convert mortals to the worship of Melora, or else to consign the faithless to death. Conflict arises if the wielder fails to further the weapon's objectives in the world. The Trident has a nostalgic attachment to the place where it was forged, a desolate island called Thunderforge. Melora imprisoned a family of Storm Giants there, and the Giants forged Wave in an act of devotion to- or rebellion against - her.

Wave harbors a secret doubt about its own nature and purpose. For all its devotion to the Melora, Wave fears that it was intended to bring about her demise in some way. This destiny is something Wave might not be able to avert.

Charges
Wave has 39 charges that can be used either for its Trident of Fish command ability or its Cube of Force. It regains 1d20 charges daily at dawn.

Trident of Fish Command
Wave can act as a Trident of Fish Command. It has 3 Charges. While you carry it, you can use an action and expend 1 charge to cast Dominate Beast (save DC 15) from it on a beast that has an innate swimming speed.

Weapon of Warning
Wave warns you of danger. While the weapon is on your person, you have Advantage on initiative rolls. In addition, you and any of your companions within 30 ft of you can’t be surprised, except when incapacitated by something other than nonmagical sleep. The weapon magically awakens you and your companions within range if any of you are sleeping naturally when combat begins.

Water Breathing
While you have Wave on your person you can speak (or telepathically communicate) the command word as an action to create a bubble of air around your head. It allows you breathe normally underwater. The bubble stays with you until you speak the command word again, Wave is removed from your person, or you are no longer underwater.

Cube of Force
You can use an action to expend a number of Charges to activate an effect. If Wave has insufficient Charges remaining, nothing happens. Otherwise, a barrier of Invisible force springs into existence, forming a cube 15 feet on a side. The barrier is centered on you, moves with you, and lasts for 1 minute, until you use an action to dismiss the cube, or Wave runs out of Charges. You can change the barrier's effect by sending a telepathic command to Wave and expending the requisite number of Charges, resetting the Duration. If your Movement causes the barrier to come into contact with a solid object that can't pass through the cube, you can't move any closer to that object as long as the barrier remains.

Cube of Force Effects:

Charges — Effect:

1 — Gases, wind, and fog can't pass through the barrier.

2 — Nonliving matter can't pass through the barrier. Walls, floors, and ceilings can pass through at your discretion.

3 — Living matter can 't pass through the barrier.

4 — Spell effects can 't pass through the barrier.

5 — Nothing can pass through the barrier. Walls, floors, and ceilings can pass through at your discretion.

0 — The barrier deactivates.

The cube loses Charges when the barrier is targeted by certain Spells or comes into contact with certain spell or magic item effects, as shown in the table below.

Spell or item — Charges Lost:

Disintegrate — 1d12

Horn of Blasting — 1d10

Passwall — 1d6

Prismatic Spray — 1d20

Wall of Fire — 1d4