Just because you can't utilize the game mechanics doesn't mean you can't work them into the story.

Davis struck the Onyx WEAPON with his Limit Break attack. It shrieked in pain.
"That's it! Keep it up!"
The group continued to assault Onyx with physical attacks, but it quickly became apparent that it wasn't working anymore.
"What's going on?"
"Maybe we should shake things up."
Chloe cast a powerful fire spell which elicited a deafening roar from Onyx.
"I think that did it."
"I think it's pissed."

Something like that.