A cortosis-armored model variation of the B2-series super battle droids which were produced in secret by the Confederacy of Independent Systems on the planet Mokivj near the end of the Clone Wars, in 19 BBY. They were manufactured in the Mokivj droid factory by Duke Solha, his brother and his sister.
When Jedi Knight Anakin Skywalker discovered the cortosis super battle droids and the factory that produced them, he considered them "unstoppable" and a big threat to the Jedi Order and the Galactic Republic. He therefore decided that he should destroy the factory that produced them along with all the already manufactured ones and the mine where the cortosis was being extracted. So that the Separatists couldn't manufacture any more droids on Mokivj. Skywalker set the mine to explode, despite the objections of Senator Padmé Amidala, Thrawn, and LebJau. The explosion was expanded by the cortosis which activated volcanic activity on the planet and caused a catastrophe.
The cortosis B2 super battle droid had the exact same weaponry as the standard model and the same height. However, the cortosis in their armor made them much heavier and also made them invulnerable to lightsabers and blaster bolts in their whole body but their optical sensors; as they weren't covered by cortosis. They were equipped with a Dual wrist blaster, like the B2-series battle droid did.
The cortosis B2 super battle droid was a variation of the B2-series super battle droid, the cortosis variation had the same firepower, height, color and sensors as the base model. They were created by Duke Solha, on the planet Mokivj, they were present in the Devastation of Mokivj, where they fought Jedi Knight Anakin Skywalker, Senator Padmé Amidala and Chiss Commander Thrawn. The factory in which they were being manufactured was destroyed along with the existing cortosis B2 super battle droids.
In 19 BBY, Count of Serenno Dooku dispatched Duke Solha, his brother and his sister to oversee mining operations, processing of cortosis, and manufacturing of the cortosis variant of the B2 and cortosis clone trooper armor on Mokivj. Solha and his siblings used a fortress built prior to the Clone Wars to manufacture cortosis clone trooper armor and the cortosis battle droids.
Cortosis B2 super battle droids participated in the raid on Solha's factory, defending the factory from the Jedi and Chiss Ascendancy attackers, cortosis super battle droids escorted Solha through the factory, protecting him from one of the attackers, Anakin Skywalker, which was a Jedi Knight. After Skywalker tried to confuse Solha's super battle droid escort, the battle droids sieged the raiders in another section of the factory.
Cortosis B2 super battle droids appeared in the 2018 novel Thrawn: Alliances by Timothy Zahn.