61 Cards

Lands:

15 Swamps
4 Marsh Flats
4 Verdant Catacombs

Creatures:

4 Nighthawk Vampire
4 Vampire Nocturnus
4 Gatekeeper of Malakir
3 Vampire Hexmage
3 Bloodghast
3 Malakir Bloodwitch
2 Kalastria Highborn

Planeswalkers:

1 Sorin Markov

Artifacts:

1 Eldrazi Monument

Spells:

3 Sign in Blood
3 Urge to Feed
3 Tendrils of Corruption
2 Mind Sludge
2 Grim Discovery

Sideboard:

3 Deathmark
3 Duress
3 Sadistic Sacrament
1 Malakir Bloodwitch
2 Mind Sludge
3 Marsh Casualties

Best Wishes

Patrick

Your story has been summoned to the battlefield – Trackback from MTGBattlefield…

The real math is more based more on what the Bushwhacker player would do.

Here are the scenarios:

1.
Opponent’s turn, do nothing (5 mana fallow, 0 mana spent).
Untap [nothing].
Vampire turn: Gatekeeper of Malakir (2 mana fallow, 3 mana spent).
Opponent’s turn [big turn]; Doom Blade (2 mana spent).
Mana spent this cycle – 5 mana

2. (reality)
Opponent’s turn, Doom Blade (3 mana fallow, 2 mana spent)
Untap [2].
Vampire turn: Nothing (5 mana fallow, 0 mana spent).
Opponent’s turn [big turn]; nothing.
Mana spent this cycle – 2 mana

So by playing the Doom Blade on the opponent’s turn, he actually spends less mana over the course of the game than if he held the Doom Blade.

Even if he never actually played the Doom Blade (after playing the Gatekeeper of Malakir), he would have spent 3, not 2, by holding the Doom Blade.

This just counts “actual” mana spent without taking into account the more elegant — or exacerbating — hoops to be jumped through with the GUT.

My point is that isn’t it clearer that the reason the play was wrong was because he spent a “card” in casting Doom Blade rather than spending the fractional “card” that comes attached to Gatekeeper? Is there a way to show through the Mana theory that he misspent his resources that is a better way of looking at it than this?

Assuming mana availability is not an issue for either player:

Turn A – Boros has one creature in play and at least two creatures in hand. Reasonable assumption would be that there’s also a land in hand for a Landfall trigger.

Least number of potential attackers: 3

Least potential damage from next attack: (3+1)+(2+1)+(1+1) = 9

So casting EOT Doomblade only reduces the potential damage by 4 and the number of attackers by 1. Even then, if the assumption is wrong and there is an additional attacker and/or the land drop is a fetch land, this action is completely negligible.

On the other hand, if Vampire did not cast his Doom Blade EOT and played his turn like this:

Turn B – Vampire kicks Gatekeeper killing Ranger, has mana open for Doom Blade

He has one potential blocker and an additional removal spell, which means he has absolutely negated 1 attacker and 4 potential damage, plus (barring removal from the Boros side) potentially negated 2 attackers. He has also successfully stalled the board (assuming no Boros shenanigans) with enough breathing room to cast a second Gatekeeper should the Boros player try to cast a relevant threat.

In other words, by following this principle of resource maximization, the Vamps player could have completely negated the advantage that the Boros player gained by playing the Ranger (again, assuming no further shenanigans by the Boros player).

Hope that helps!