Negative Onslaught is a Mister Negative deck, using onslaught along with Iron Man and Mystique, to ramp up power. The Living Tribunal applies the master effect; it splits your total power among all locations. As a result of this ability, you can put together something such as Iron Man - Onslaught - Mystique - Blue Marvel to decimate your opponent on all three lanes. Although Onslaught itself has a bad interaction with Mister Negative, this deck works in a similar manner to Negative Jane, where you hope to have Onslaught in your opening hand. Ideally, include either Zabu or Psylocke. I would recommend adding Electro to any other Living Tribunal deck, to make the decks viable.
Please note that some of the variants, and The Living Tribunal are unreleased, as of the creation of this deck.