Infernal Contract Artifact: Sign away your life blood to receive a surge of Embers! Trace the design to activate the contract.
Sacrifice 20%-30% of your current HP to gain two embers which immediately appear on the platform you're already on. You'll pay a smaller total penalty if you wait until your hit points are half gone before using this.
When you do this, your hit point bar lights up for your opponent to see your life drain away. A savvy opponent will instantly recognize what you just did. Take cover first if you need subtlety.