Leviathan nanofins

Fins. Leviathan had fins.

They were like blades, points sweeping backwards. A fin rooted in the side of his arm, from wrist to elbow, the point scything back. Had it not been limp enough to trail on the ground, it might have reached his shoulder. More at the sides of his neck and along the length of his spine, forming an almost serrated pattern where multiple fins overlapped. Perhaps some at his legs. The fins ran down the length of his tail, and ended in a cluster at the end, like the tuft of fur at the end of a lion's tail, exaggerated many times over in size.

He flexed a claw, and I could see webbing between each finger, mottled in black and an iridescent green that matched his eyes. It made me think of the bioluminescence of a jellyfish in the deep ocean.

In synchronous motions, the Simurgh unfurled her wings, stretching them to their full length, and Leviathan flexed his fins, letting them unfold in kind. Each fin was the same as the webbing, mottled black and a eerie green, and the echo-image of water that accompanied his movement produced mist as it washed over the fins. It obscured him almost completely, and as much as the pouring rain served to drive it away, the rainwater produced more mist as it touched the fins.

[...]

"Upgraded Leviathan," Tattletale said. "Attuned some device to the right frequency or setting, then tapped into his core without doing too much harm to Leviathan. Fed things into there. Knowledge, data, nanotechnology."

Defiant's head turned, as if Tattletale had said something.

"Yeah," Tattletale said. "Nanotech. Why do you think the fins were turning water to mist?"

"My tech?" Defiant asked.

"Among one or two other advancements. If the density rules are in effect, I'd bet those fins are just as hard to cut through as Leviathan's arm or torso. Disintegration effect, maybe something else."

- Cockroaches 28.5