"I feel it...This is Akane Shinjo's heart itself!"
- ―Gridknight describing the monster's second form.
Subtitle: **** Monster (****怪獣 **** Kaijū)
This was the first kaiju to appear in over a week, being selected by Akane Shinjo among several incomplete figures after Alexis・Kerib pushed her into making a new kaiju. It was easily dealt with by Full Powered Gridman, who launched the Breast Spark at it. However, unlike other kaiju, its corpse did not explode.
Later, something else emerged from the "corpse" and began to wander around decapitating the Venoras, clearing the fog around the city. Full Powered Gridman was called into action once more, but was easily defeated by the creature because of its unpredictable and powerful attacks. The monster then began tearing the Assist Weapons off of Gridman and strangled him, until Anti arrived, knocking the monster aside. It then shot both of its opponents with a destruction ray, but Anti got in the way to protect Gridman. Battling alone, Anti evolved into Gridknight, and was able to match his enemy. Gridknight finished off the kaiju by slicing it in half using his new cutting halo attack.
It, along with all the other kaiju Gridman fought, reappeared when they were summoned by Alexis to get rid of Gridknight, since Akane refused to make any more new kaiju. It was finished off along with Gonglee when Gridknight sliced them in half using the Gridknight Circular.
- Designer: Masaru Sakamoto
- Underneath the head of the "suit", above the line on the neck, are dots that are made to resemble eyeholes of older/cheaper tokusatsu suits.
- The kaiju's first form can be seen as a counterpart to Teleboze from Denkou Choujin Gridman; as the two were both weaker creatures of a similar build, only to have a more menacing and powerful second form.
- Nanashi B's death is done in the same way as Shinobilar: both tried to disorient their opponents with high speed attacks until they were killed by an incoming slicing projectile.
- Its 'A' form is designed to resemble a soft vinyl (sofubi) figure, hence the lines on the neck, shoulders and groin, which are based off articulation points on sofubi figures.
- According to scrapped concept art shared by character designer Masaru Sakamoto on Twitter, Nanashi B's head was meant to be able to open up and reveal a mouth and tongue.
- Height: 77 m
- Weight: 20,000 t
- Powers and Weapons
- Pink Lightning Ray: The monster can fire a stream of pink lightning from somewhere on its head.
- Height: 65 m
- Weight: 18,000 t
- Powers and Weapons
- Strength: It has incredible strength, being able to physically harm Full Powered Gridman as well as tear the Assist Weapons off his body.
- Agility: The monster is incredibly fast and agile, being able to dodge a barrage of missiles fired at it.
- Energy Beam: A very powerful energy beam fired from its "eye", it can defeat Full Powered Gridman in one shot.
- Instant Decapitation: Simply by walking past them, it can somehow decapitate the Venoras.
- Unpredictability: The monster's unpredictable moves and behavior prevent Gridman from anticipating its assaults, or land an attack on it. Despite this, Anti's Gridknight form can keep up with its speed and eventually defeated it.