Mechamaru Mode: Absolute is a giant mechanical armored puppet created under the trial production number zero. It is a massive cursed corpse that can be piloted using the cockpit area in the head.
Inside, there is a driver's seat suspended from the top of the cockpit area via several mechanical tubes. The diver's seat itself is slim and the driver's feet can rest on a circular fixture attached to the bottom of it. Mode: Absolute's piloted using two pulley-like handles fastened to the user's hands that are also connected to the roof of the cockpit with long wires. This allows the pilot to move the puppet's limbs as they do, granting them a full range of control. It also features a communication device and sensory feedback settings. 
This version of Mechamaru is not only much larger but defensively its armor is far more durable and offensively it can momentarily output special grade levels of cursed energy. The inside of the cockpit has an uploader function that allows the user to insert tubes imbued with cursed techniques called a Jujutsu Technique Charge (
During his years in isolation, at some point, Kokichi developed the giant armored version of Mechamaru. After having his body healed by Mahito's Idle Transfiguration, Kokichi was finally healthy enough to pilot the goliath by himself, using it to combat Mahito. It was hidden underground, apparently beneath a riverbank.
Mode: Absolute is fueled by Kokichi's entire life's worth of cursed energy; seventeen years, five months, and six days. The highest area of concentration in the suit is inside the head, making it simple for Mahito to sense where Kokichi is piloting it from.
Kokichi mainly combats Mahito with Ultimate Mechamaru using a combination of different energy-based attacks as well as physical blows. Energy beams like Ultra Cannon use entire years worth of cursed energy in their blasts, burning their targets with massive explosions. Mahito initially brushed them off, believing this type of offense wouldn't be able to injure his soul.
Mahito's enlarged fists are strong enough to threaten to break Mechamaru's armor, but it holds up after the first direct hit. Kokichi switched up his approach by utilizing cursed technique charges using the tube uploader, allowing Mechamaru to activate Simple Domain. The fingers on Mechamaru's right-hand change form into a spike or a projectile capable of affecting its target with Simple Domain. This allowed Kokichi to damage Mahito's soul and follow up with a flurry of physical strikes using the giant puppet. Even Geto admitted this strategy was very effective against Mahito. The curses only counter is to activate his Domain Expansion.
However, the barrier technique charge protects the cockpit area with Simple Domain. Once Mahito believes he's won, Kokichi uses a surprise attack to insert the cursed technique into Mahito directly by stabbing the giant spiked finger into the curses' body. This initially appears to kill Mahito, leaving Kokichi with nine years' worth of cursed energy to fight Geto with. Unfortunately for Kokichi, Mahito survives and breaks into the cockpit area, leaving the pilot completely exposed to attack.