Two words. Street Justice. Poke from a distance until you, or someone else can get her around/below half health, and when she's not using earthen guard, pounce.

The best way to get Torvald down is the combo between Wrecker and Street Justice. Keep your distance if you know Nullify is up, because Nullify is your ruin. Knock his health down from a distance, rush in, and pounce once hes at/below half health.