Too bad the rest of the crew can't keep up. Apart from Myranda and Waldgeist none of the original book beasts have scout, so if you happen to play on a dense-terrain board the army's at a disadvantage compared to other masters. The new book redresses the balance with all that flying, but his list is still slower, overall, than Nephilim luftwaffe.
Yes, the chances of that happening are very small. You have to have a good hand, good flip, and the enemy has to have very poor hand and flips. Much more likely is that you'll hit Lady J for 4-6 damage, and then she activates and turns Marcus into catfood. In fact, most masters can turn him into catfood, and a good deal of minions as well. He's a melee master with sub-par attacks, he's a buffer master with one, weak buff, and he's a control master whose control spell is insanely expensive and hard to pull off. All in all, he's best treated as another, 7-8SS beast rather than a "real" master in game.