This deck has been revamped and is now more viable. The ridiculous growth of the counters has however been removed. The new version can be found here.
Built around Varolz, the Scar-Striped in an effort to utilize his scavenge ability and place counters on a creature which is hard to get rid of and hard hitting: the Lotleth Troll.
Death's Shadow is one of the key cards in the deck and are meant to be thrown directly in the graveyard. This can be done by playing the card anytime you're at or above 13 life. Another way to do this is to play Jarad's Orders, find a card you need on your hand and throw the Death's Shadow away. Preferably though, the card is discarded from the hand using the ability of the Lotleth Troll in order to get a free +1/+1 counter.
The Lotleth Troll is meant as the main attacker, as they can be regenerated and as such minimize the risk of losing the counters placed on it. It also has trample, which removes the need to have an enchantment such as Rancor and has a free discard ability to get rid of the Death's Shadow.
Sylvan Caryatid is meant to speed the deck up, as they can be used as any colour of mana. Furthermore they are excellent placeholders for +1/+1 counters, should you have no Lotleth Troll on the board, as they are hexproof. They also have the benefit of being a rather tough creature and can be used as blockers, should it be needed.
Corpsejack Menace has the ability to turn a single +1/+1 counter into a +4/+4 counter if both are on the board, while Bioshift is meant to either save counters, should a creature die, or to multiply existing counters through Corpsejack Menace. While more could be added to the deck to turn every +1/+1 counter into a +16/+16 counter, this slows the deck down, and having a single one on the board is devastating enough already.
Swiftfoot Boots are in the deck mainly to protect either Varolz, the Scar-Striped as he is the key to this deck and is rather vulnerable, or to protect Corpsejack Menace should you feel that you have scavenged enough and would rather multiply counters with Bioshift
Finally the Essence Harvest can be used to destroy an opponent even if he has damage prevention, and in a scenario where you play against others it also leaves you with a potentially huge healthpool. Guttural Response is in the deck to insure that Essence Harvest will go through, as most counterspells are blue.
The deck is also equipped with a variety of utility spells for destroying, saving creatures, retrieving dead creatures or spells and finding what creatures you might need in your library.
TL;DR Varolz, the Scar-Striped scavenges Death's Shadow for counters on Lotleth Troll. Counters are multiplied with Bioshift
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Corpsejack Menace