Mighty Servant of Leuk-o (Item)

From Tasha's Cauldron of Everything, page 131.

Description
Wondrous item, artifact (requires attunement)

Named for the warlord who infamously employed it, the Mighty Servant of Leuk-o is a fantastically powerful, 10-foot-tall machine that turns into an innate construct when piloted. Exalted of a gleaming black alloy of unknown origin, the servant is often described as a combination of a disproportioned dwarf and an oversized beetle. The servant contains enough space for 1 ton of cargo and a crew compartment within from which up to two Medium creatures can control it — and potentially execute a spree of unstoppable destruction.

Tales of the servant's originals involve more conjecture than fact, often referring to other worldly beings, the mysterious Barrier Peaks of Oerth, and the supposedly related device known as the Machine of Lum the Mad. The best details on the device's origins and operation can be found in the Mind of Metal, a tome of artificer's secrets that connects the device to the tradition of the lost Olman people, and which was written by Lum the Mad's several times over granddaughter, Lum the Maestro, while she reconstructed the long disassembled Mighty Servant of Leuk-o.

Dangerous Attunement. Two creatures can be attuned to the servant at a time. If a third creature tries to attune to it, nothing happens.

The servant's controls are accessed by a hatch in its upper back, which is easily opened while there are no creatures attuned to the artifact.

Attuning to the artifact requires two hours, which can be undertaken as part of a long rest, during which time you must be inside the servant, interacting with its controls. While crew members are attuning themselves, any creature or structure outside and within 50 feet of the servant has a 25 percent chance of being accidentally targeted by one of its Destructive Fist attacks once during the attunement. This process must be undergone every time a creature attunes itself to the artifact.

Controlling the Servant. While any creatures are attuned to the artifact, attuned creatures can open the catch as any other door. Other creatures can open the hatch as an action with a successful DC 25 Dexterity check using thieves' tools. A Knock spell cast on the hatch also opens it until the start of the caster's next turn.

A creature can enter or exit through the catch by spending 10 feet of movement. Those inside the servant have total cover from effects originating outside it. The controls within allow creatures to see outside without obstruction.

While you are inside the servant, you can command it by using the controls. During your turn (or either attuned creature), you can command it in the following ways:
 * Open or close the hatch (no action required, once per turn)
 * Move the servant up to its speed (no action required)
 * As an action, you can command the servant to take one of the actions in its stat block or some other action.
 * When a creature provokes an opportunity attack from the servant, you can use your reaction to command the servant to make one Destructive Fist attack against that creature.

While there are no attuned creatures inside the servant, it is an inert object.

Ghost in the Machine. Upon his death, the soul of the mighty warlord Leuo-o was drawn into the artifact and has become its animating force. The servant has been known to attack or move of its own accord, particularly if doing so will cause destruction. Once every 24 hours, the servant, at the DM's discretion, takes one action while uncrewed.

If the servant loses half of its hit points or more, each creature attuned to it must succeed on a DC 20 Wisdom saving throw or become charmed for 24 hours. While charmed in this way, the creature goes on a destructive spree, seeking to destroy structures and attack any unattuned crratures within sight of the servant, starting with those threatening the artifact — preferably using the servant, if possible.

Self-Destruct. By inputting a specific series of lever pulls and button presses, the servant's two crew members can cause it to explode. The self-destruct code is not revealed to crew members when they attune to the artifact. If the code is discovered (the DM determines how), it requires two attuned crew members to be inside the servant and spend their actions on 3 consecutive rounds performing the command. Should the crew members begin the process of entering the code, though, the servant uses its Ghost in the Machine property and turns the two crew members against each other.

If the crew members successfully implement the code, at the end of the third round, the servant explodes. Every creature in a 100-foot-radius sphere centered on the servant must make a DC 25 Dexterity saving throw. On a failed save, a creature takes 87 (25d6) force damage, 87 (25d6) lightning damage, and 87 (25d6) thunder damage. On a successful save, a creature takes half as much damage. Objects and structures in the area take triple damage. Creatures inside the servant are slain instantly and leave behind no remains.

This does not destroy the servant permanently. Rather, 2d6 days later, its parts — left arm, left leg, right arm, right leg, lower torso, and upper torso — drop from the sky in random places within 1,000 miles of the explosion. If brought within 5 feet of one another, the pieces reconnect and reform the servant.

Destroying the Servant. The servant can be destroyed in two ways. After it has self-destructed, the disconnected pieces can be melted down in one of the force temples of its ancient Olman creators. Alternatively, if the servant strikes the Machine of Lum the Mad, both artifacts explode in an eruption that is three times the size and three times the damage as the servant's self-destruct property.