Forged Destiny [Book 2: Ch. 13]

"It's weak to fire!" Ruby yelled. "Everyone, try and use fire attacks!"

[...]

No, wait… my eyes shot to the side, and an idea formed in my mind. I staggered forwards, pushing myself on as I rushed over to a puddle of the black liquid Kaedin summoned. It wasn't much, but it looked like it splashed away from the rest and hadn't caught fire. I knelt and dipped Crocea Mors into it, dousing the steel as liberally as I could. Once it was slick enough to distort my reflection, I rushed back into the fight and looked for an opening.

[...]

I drew the sword up to my shoulder, pressing the pommel against it as I lunged for its side. The blade bit deep, sunk in – and then lodged once more in whatever muscle lay within. There was no response at first, although it was nearly torn from my hand from its movement. I clung on, however, and growled as I touched the fingers of my right hand to the blade's fuller.

My eyes flashed bright blue.

Crocea Mors flickered, and then roared. The oil ignited immediately, blue and yellow flames racing across steel and taking full advantage of how the flammable liquid pooled in the fuller. I watched with narrowed eyes as the flames consumed its skin, but also as the fire burned inside it.

Merlot shrieked in agony.

This time, the sword was torn from my hand, but only because the body it was stuck into thrashed and flailed wildly. The flames penetrated deep, licking along the sword and into the creature's body.

—Forged Destiny [Book 2: Ch. 13]