Pyromancy 8

Liliana was quite certain her power exceeded Baltrice's, yet the fight was going poorly. Though she lacked Tezzeret's ability to command and control the machines that made up the great artifact, Baltrice knew its ins and outs well enough. At her whim, pipes overheated, sending bursts of steam or flying shrapnel to tear the flesh from her foe. Worse still, she knew which conduits carried the mana-infused gasses that Tezzeret used to replenish his own powers, knew how to tap into them with a simple spell. Liliana, who could only struggle to leach the ambient energies directly through the walls, found herself growing steadily weaker, while her enemy, though wounded deeply by the touch of dead and deathless things, remained strong.

Agents of Artifice (Magic The Gathering: Planeswalker Book 1), Chapter 31