Legion doesn’t feel pain, but Cairax hurt him

When the first one jumped on him he thought it was the Dragon’s new trick. Somebody with telepathic-ness or whatever you called moving stuff with your mind. But none of the Dragon’s people were that savage. Even when Stealth fought, she was intense, but never sadistic.
It was fast and brutal and ruthless, like wrestling with a hungry pit bull. A smart, hungry pit bull crossed with a piranha. He’d thrown more exes at it and it had fought back with more of its own.
…
He had millions of bodies, every one of them tireless and numb to pain.
Numb until today, anyway. Whatever was using the other exes had hurt him. A lot. He’d felt every body get slashed and torn apart. And for a few moments it had held him there, like holding a geek’s forehead and watching them swing useless punches. He hadn’t been able to shift away.
He hadn’t been able to do anything.

Excerpt From Ex-Communication, pg 372
Peter Clines
https://books.apple.com/us/book/ex-communication/id635706546