Let me introduce you my Grakmaw, Skyclave Ravager deck! It is a voltron style deck, built on this hydra horror, who has 3 abilities. My opinion is, that his second ability is really a „hard to be used” one, it would require plenty of time to cast little creatures with counters to the board, put out a sec outlet, summon Grakmaw and start sacrificing the little minions for counters. So this ability is really just an optional one, but his third ability is actually strong. It means, you will have a creature after a board wipe, a create with the same size as Grakmaw when he died. In other words the opponent has to face this manace twice, and eliminate him twice, - which is quite good. Therefore our strategy is really simple: pumping Grakmaw rapidly as big as we can. Thanks for the Black and Green color, we have tons of cards that fit to this purpose: Evolution Sage, Forgotten Ancient, Ivy Lane Denizen, Loyal Guardian, Pridemalkin, Rishkar, Peema Renegade, Verdurous Gearhulk, Winding Constrictor, Hardened Scales,Ordeal of Nylea,Path of Discovery, ,Find / Finality,Vastwood Surge,Animation Module, Vivien, Arkbow Ranger, Ring of Kalonia.
I would highlight those ones, that have doubling effect like: Corpsejack Menace, Kalonian Hydra, Invigorating Surge,Solidarity of Heroes, Biogenic Upgrade, Hydra's Growth. With these cards you can pump up Grakmaw to the skies, and even if the opponent kills him somehow, if you get a 20/20 token when he dies, - it is a fair deal. On the other hand, the deck operates with „Power Matters” cards, so the mentioned 20/20 token is a good base when you seek for a creature with high Power to draw cards upon it. (Garruk, Primal Hunter, Rishkar's Expertise.)
Unfortunately Grakmaw does not have an evasive ability, so we have to take care of him, and make him able to hit the opponent. The easiest way is adding Trample to our Hydra, which can be done by Pridemalkin, Ring of Kalonia, Garruk's Uprising, or Vivien, Arkbow Ranger. You also can make him unblockable with cards like Shizo, Death's Storehouse or Rogue's Passage. It also works, if you simply eliminate your opponents creatures, since the deck has 10+ creature removel spells like Toxic Deluge or Maelstrom Pulse. Since counters really matter in this deck, our lands also can support this purpose: (Guildmages' Forum,Karn's Bastion,Llanowar Reborn, Opal Palace, Oran-Rief, the Vastwood). I know that for example Guildmages' Forum is not really a competitive card, but the +1 counter it can give to Grakmaw matters, if this lifts him up a bit to survive your own Toxic Deluge strike.
Finally, I would mention some cards that work surprisingly well in this deck:
Primal Might: It is devastating that you can pump up your commander and destroy an opponent’s creature with a single card.
Parting Thoughts: Multi-functional card in this deck. It can kill an opponent’s creature, or you can apply it against one of your creature to draw lots of card.
Vivien, Arkbow Ranger: In early games she is a wincon. Plus one counters and trample are the only things that Grakmaw needs to eat up an opponent.
Phyrexian Scriptures: A counter to the hydra, then destroying the whole board except him, assures a slot for this card in this deck.
Ordeal of Nylea: An excellent card, especially in early games, to ramp a bit and pump up the commander.
Rancor: A recurring card that provides Trample, - an essential condition to win.
Lifeblood Hydra: Funny to see him as a 12/12 creature with trample, since it causes a dilemma to the opponent. Let him in, and losing life, or kill him, and make me draw tons of cards.
Incubation Druid: Try to bring her with a +1 counter to the board (Llanowar Reborn,Ring of Kalonia), so she can provide you 3 mana immediately.
Ivy Lane Denizen: I found it better than Reyhan in this deck. With Avenger of Zendikar or Iridescent Hornbeetle it can be a wincon (adding counters to Grakmaw).
Jarad, Golgari Lich Lord: He is also a wincon (sacrificing an enormous Grakmaw and his child), if the game is too passive and we can not risk even a single attack.
Overwhelming Stampede: The is no green based Voltron deck without this.
I hope you will enjoy playing with this deck! If you have any questions, feel free to address them to me! Thank you!
