Orbalisks in battle and output:

For several seconds he simply stared at the empty pedestal, feeling the pulsing hunger of the orbalisks and his own gathering rage. A red veil fell across his vision, and Darth Bane surrendered himself to the fury.
...
The camp was in ruins. The tents were leveled, their canopies shredded and torn. Wooden supply crates had been smashed into sawdust and splinters, their contents tossed and scattered on the wind. Hundred-kilogram fuel cells lay strewn about the campsite, some thrown fifty meters from where they had been stored.
The ground was littered with debris and marred by dozens of still-smoldering black scorch marks Zannah recognized as the remnants of a terrible storm of unnatural lightning. The air still crackled with the power and energy of the dark side that made her tingle in fear and anticipation.
It was easy enough to guess what had happened. Bane had failed yet again in his attempt to create a Holocron, then in a blind rage lashed out at the world around him with all the power of the Force.

---

The chamber beyond was enormous, at least fifty meters long and easily twenty wide.
Once a mutated combination of flesh and technology, most of the technobeasts' living tissue had long since rotted and fallen away. What remained were desiccated strands of skin and sinew clinging to bone, supported and held together by rods, wires, and twisted scraps of metal.
...but the inevitable long-term degradation had impaired their motor skills and reduced them to shells of shambling, mummified metal.
He made his way slowly through their legions, trying to estimate their number as he edged ever closer to the center of the room. Fifty? A hundred? It was impossible to count; their bodies of rusted metal and mummified flesh all seemed to blend together into a single ghastly mass.
...a hundred mechanized limbs sprang to action with an angry hum as the monsters swarmed over him.
Bane thrust out with the Force, and a dozen of the oncoming creatures exploded into dust and tiny flecks of small, twisted metal.
Even in their rage, the creatures were slow and cumbersome.
He rose to see the wall of creatures pressing in on him, and he unleashed a wave of lightning through their ranks. The bolts arced through the mostly metal bodies; the nanotechnology that animated their frames and gave them life smoked and smoldered, and a dozen more of his opponents toppled over never to rise again.
...he used the Force to disintegrate two more advancing technobeasts, then felt something bump against his foot. 
The slaughter lasted over an hour. He used his lightsaber to repeatedly dismember his enemies, conserving his Force abilities to stave off exhaustion in arms, legs, shoulders, and back. Three times during the one-sided melee he allowed himself to lose focus, his martial instincts thrown out of sync by the unnerving silence of his enemies as they were butchered. Each time his attention lapsed he was knocked to the ground by the blows of one of the lumbering creatures that got close enough to make contact and forced to battle his way back to his feet. 

---

Bane snarled in anger at her betrayal, his rising anger fueled by the chemicals the orbalisks were pumping into his system.
...
Bane spun and thrust his open palm toward them, lashing out with the power of the dark side. Like the Jedi and Sith, one of the first techniques Shadow Assassins learned was the creation of a Force barrier. Channeling their power, they could form a protective shield around themselves to negate the Force attacks of their enemies. But if an opponent was strong enough, a concentrated attack could still breach the barrier. Darth Bane, Dark Lord of the Sith, was definitely strong enough.
Two of the assassins were stopped in their tracks, knocked to the ground as if they had run into an invisible wall. Two more, weaker and less able to defend themselves against Bane's power, were sent flying backward. Only the fifth was strong enough to resist the Sith Lord's throw and continue his charge.

---

As he fell to the ground, Zannah turned her attention to Bane on the far side of the room. He was single-handedly battling three Jedi, slowly pushing them back toward where the Ithorian lay crumpled in a corner.
Gathering the dark side around her, Zannah created a concealing cloak to mask her power as she had done at the Jedi Temple. While she did so, she saw the Ithorian slowly rise to his feet and close his eyes in concentration. She felt the surge of light-side energy rolling across the room, as did Bane's opponents.

---

In the corner the Ithorian broke his meditative trance, sensing that his companions had fallen. But before he could act Bane leapt through the air and landed in front of him, slashing all four of his throats simultaneously. The Ithorian crumpled to the ground, and Bane turned to finish off the one-handed Jedi.
Zannah felt the gathering dark side power of her Master, but in the instant before he unleashed the storm of deadly purple lightning, the Ithorian reached up from the floor and clutched him by his ankle. A shimmering blue globe surrounded them both as the mortally wounded Jedi released his own power in his final, dying act.
Instead of arcing across the room to destroy the one-armed Jedi, the lightning that flew from Bane's fingers reflected off the inside of the shimmering blue globe encasing him. The bolts ricocheted around wildly inside the globe, creating a storm of energy so intense that Zannah had to shield her eyes and look away. She heard Bane's scream rising above the sharp crackle of electricity, and when she looked back she saw the globe vanish and her Master fall to the ground in a charred and smoking heap.
...
...he remembered unleashing a storm of Force lightning at the last of his foes. He remembered the kriffing shield the Ithorian Master had thrown up around him. After that, all his memories were of unbearable pain.
Somehow the Jedi's barrier had trapped Bane inside the center of the dark side storm. The electricity had enveloped him, millions of volts arcing through his body, cooking his flesh from the inside and throwing his muscles into an endless series of violent seizures that threatened to rip his body apart.

- Darth Bane: Rule of Two