Venom

"Venom" (ヴェノム Venomu) is an archetype of cards used by Professor Viper in the Yu-Gi-Oh! GX anime and introduced in Tactical Evolution. They focus on the distribution of Venom Counters via "Venom Swamp", while their strongest monsters (which are not technically a part of the archetype, but related to it) gain ATK for each Reptile-Type monster in the Graveyard. "Vennominaga the Deity of Poisonous Snakes" gives an alternate win condition via its Hyper Venom Counters.

Since they rely upon Reptiles being sent to the Graveyard, Venom Decks are at their most vulnerable when banish strategies are used, like "Dimensional Fissure". They are also at risk of losing Life Points early, since the only reliable methods for quickly Summoning "Vennominon the King of Poisonous Snakes" from the Deck involve taking Life Point damage (either via "Damage = Reptile" or "Damage Condenser".) All other "Venom" monsters happen to have low ATK for their Level as well, so it is difficult for a "Venom" user to take the offense to the opponent early, especially if "Venom Swamp" is not yet on the field.

These cards can combo well with other Reptile archetypes such as "Alien", "Reptilianne" and "Worm".

Playing style
The Deck focuses on lowering the opponent's monsters' ATK with "Venom Swamp" and Summoning "Vennominon the King of Poisonous Snakes" or "Vennominaga the Deity of Poisonous Snakes". Since the ATK of both cards are dependent on the number of Reptiles in your Graveyard, cards like "Foolish Burial" and "Snake Rain" are important in this Deck. Also, there are not many "Venom" monsters, so a hybrid with other Decks is inevitable.

"Venom Swamp" is able to quickly weaken and eventually destroy any non-"Venom" monster. Also, even if "Venom Swamp" is not on the field, "Venom Burn" can inflict serious damage to a player's Life Points. In addition, the ace card of this Deck, "Vennominaga the Deity of Poisonous Snakes", is almost invincible since it cannot be destroyed by any means except by battle, and can only leave the field by Tributing it with cards like "Volcanic Queen" and "Lava Golem", though even this can be countered with "Fog King" or "Mask of Restrict".

The Deck relies on "Venom Swamp" for Venom Counters to have any effect on monsters, so if "Venom Swamp" is destroyed, Venom monsters' effects are useless. This bad situation can be avoided by "Spell Reclamation". This will greatly help in a Venom Deck, as when Venom Swamp is destroyed, it is returned to your hand. In addition, Summoning "Vennominaga the Deity of Poisonous Snakes" is difficult since you need to Summon it with "Rise of the Snake Deity", meaning that a mere "Seven Tools of the Bandit" or even "Malfunction" can ruin your chance.

The main weakness of the "Venom" Deck, however, is the low ATK points of most "Venom" monsters. This means that your opponent can easily just Summon a monster to destroy your Venom monster, ignoring "Venom Cobra". Because of this, cards like "Ambush Fangs" and "Negate Attack" are essential to this Deck.

Another weakness of this Deck is "Zombie World". This card should make the ATK of "Vennominaga" 0, plus when destroyed there would be no Reptile monsters to banish for bringing her back. To stop this its important to have a "Field Barrier" protecting your "Venom Swamp".

Important Support

 * Evil Dragon Ananta -- In the event that attempting to summon Vennominon or Vennominaga fails, this card can be very powerful as a backup by banishing all Reptiles in your field and Graveyard.
 * The Tyrant Neptune-- a great backup plan is summoning this card if you find yourself without Venominon. Tribute Summon this card with at least 1 Venom Monster to make this card immune to the effects of Venom Swamp and allow it to distribute Venom Counters in place of your weaker monsters. Also, if Vennominaga is destroyed and there are no Reptiles left to banish, use this card's effect to gain Vennominaga's ability to gain counters for an instant win.
 * Snake Rain -- Sends 4 Reptiles to the Graveyard from the Deck, powering up Vennominion or Vennominaga by 2000 ATK. In addition, if you discard a Reptile monster for the cost, that's another 500 bonus ATK points.
 * Damage = Reptile -- Allows the easy summon of Vennominon, since its original ATK is 0. Make sure to have at least a few Reptiles in the grave before summoning him with this, however.
 * Snake Whistle -- Summons another low-level Reptile when one you control is destroyed by effects, which can be handy.
 * Damage Condenser -- Allows the summon of Vennominon in the event you do not have any Reptiles on the field at all.
 * Destructive cards that target your own monsters -- Since "Rise of the Snake Deity" cannot activate in response to cards that would make Vennominon leave the field without destroying it, it is usually more reliable to destroy Vennominion yourself. The Trap Card "Offering to the Snake Deity" was specifically designed for this effect.  Tribute to the Doomed, Offerings to the Doomed and Hammer Shot are some of the other better choices for this.  Note that cards like Thunder Crash won't work, since they cause Rise of the Snake Deity to miss its timing.
 * Non-Venom Reptiles -- Vennominon and Vennominaga benefit from any Reptile in the graveyard, not just Venoms. Some of the better ones to include in a Venom Deck are Reptilianne and Worm monsters.
 * Vengeful Bog Spirit -- Prevents monsters from attacking on the turn they are summoned. When Venom Swamp is in play, this will weaken opposing monsters by 1000 ATK before they are able to make their first move. If you have a face-up Venom Boa, this will ensure that almost any non-tribute monster your opponent summons will be destroyed before they even get a chance to use them.
 * Stumbling -- Another great card like Vengeful Bog Spirit to make monsters lose 1000 before attacking, and combined with light of intervention means that your opponent can only summon monsters in face up defence position... the downside being so can you. This can cause problems without venom swamp or if they have a monster which can survive long enough with enough attack to destroy your defense position venoms, however unlikely that is.
 * Light of Intervention -- Venom Swamp can't place counters on face-down monsters--with this, even a defending opponent will be losing their monsters rapidly.
 * Final Attack Orders -- Will allow Vennominon and especially Vennominaga to inflict battle damage upon the opponent most easily, especially since Vennominaga cannot be equipped with a card that would grant it piercing damage. Make sure to activate Final Attack Orders only when ready, however, as most Venom monsters are quite weak compared to most monsters.
 * Solidarity -- Boosts the ATK of your "Venom" monsters, which alleviates their main survivability issue. If you use this card, you cannot use non-Reptile-type monsters, although not many would fit into this Deck anyway.
 * Viper's Rebirth -- If you're using Solidarity, use this card as well. The best use of this card is to summon Vennominon and let it destroy itself, thus triggering Rise of the Snake Deity. Also, since the effect takes place during the end phase, summoning Vennominaga is faster.
 * Venom Burn -- Helpful if you're racing your opponent for damage and you need that last little push for the win. A particularly useful strategy is targeting your own monsters. If you're running non-venom beatsticks like Evil Dragon Ananta or Earthbound Immortal Ccarayhua, it instantly brings them back to full strength and hits your opponent hard for damage in a devastating one-two blow.
 * Metal Reflect Slime -- A very useful stall card. Not only is its 3000 DEF capable of blocking attacks from most monsters (a trait that is powered up by Venom Swamp's ATK-reducing ability), but its 0 ATK makes it immune to Venom Swamp. This will keep it on the field both for defending against your opponent and accumulating Venom counters that you can use as ammo for Venom Burn.

However, adding Reptile-Type monsters is a disadvantage because while Venom Swamp is on the field, not only your opponent's monsters will have Venom Counters, so will yours if they don't have "Venom" in their names. This will cause your monsters to be destroyed as well. However, you can use Venom Burn and take out the Venom Counters from your monsters and inflict damage to your opponent.