"Cosmic Compass" can also be used to benefit from the effect of "Obelisk". To destroy all of your opponent's monsters, play this card right and a deadly arsenal of Tributes for the price of one card.
The effects of the "Piece Golems" can speed up this card's Summoning considerably.
A good combo to use with the effect of "Obelisk the Tormentor" is to include cards that can be Special Summoned easily therefore getting monsters on the field to activate the effect of "Obelisk" to Tribute two monsters to destroy all of your opponent's monsters.
"Fires of Doomsday" can be used for this card's ability to destroy all monsters your opponent controls.
A decent way of preventing your "Obelisk" from falling into the hands of your opponent from "Creature Swap" since it does not target (given if it is your only monster out on the field), the card "Pole Position" can be used to prevent it from happening since the card does not target your "Obelisk" and negates Spells from affecting the strongest monster out on the field.
However, be careful when using this strategy, as "Pole Position" may also destroy "Obelisk" when it leaves the field.
A good combo to Summon this card is to use "One for One" in combination with "Destiny HERO - Malicious" and "Evil Thorn". Discard "Malicious" with "One for One" and Special Summon "Evil Thorn". Activate the effect of "Evil Thorn" in order to Summon two more. Then use the effect of "Malicious" to Summon another copy and then Tribute all three to Summon "Obelisk the Tormentor".
When there are five monsters in your Graveyard, use "Soul Charge" to Summon those monsters, and then Tribute three of them for "Obelisk the Tormentor". The other two can be used for its effect. You will lose your Battle Phase, but "Obelisk" cannot attack the turn its effect is activated anyway.
Use your opponent's monsters as Tributes for this card's effect using "Soul Exchange". The Battle Phase-skipping effect won't matter since this card cannot attack anyway, however this is only effective when your opponent have at least 3 or more monsters.
With some good Insect-Type monsters to put in your Graveyard, "Spider Egg" can both protect yourself from an attack and Special Summon 3 "Spider Tokens", providing another way to Summon this card.
To temporarily prevent this card from being destroyed by battle, "DNA Transplant" and "Honest" can be used. Since neither cards target "Obelisk", by having "DNA Transplant" having your monsters be LIGHT monsters, should your opponent happen to have a monster stronger than "Obelisk", "Honest" can be discarded to prevent it from being destroyed by battle and inflict 4000 points of damage to your opponent.
"Machine Duplication" can placed monsters on your field quickly, allowing yourself to Tribute them to Summon this card or activate its effect. This can be combined with "Magnet Circle LV2" or "One for One" to get "Obelisk" out instantly.
This card can be easily Summoned in a "Frog" Deck thanks to "Treeborn Frog" and "Ronintoadin". "Frog" Decks also Summon quickly enough to use "Obelisk" even without "Treeborn".
If your opponent's field is full, "The Tricky" and "Tricky Spell 4" are a good combo to both Summon this card and use its effect to instantly clear your opponent's field.
Use Photon Veil to get 3 copies of "Watapon" and Special Summon them by the effect of "Watapon", then Tribute them for "Obelisk".
This card works well in a "The Seal of Orichalcos" Deck; your opponent cannot attack your weak monsters while "Obelisk" is on your field.
With the introduction of Pendulum Summoning, gathering fodder for the Summoning and effect of "Obelisk" is effortless. Once "Obelisk" is in play, Tribute 2 Pendulums for its effect, then Pendulum Summon them right back into play for a swarm of free direct attacks.
Among the best choices to remove it are with cards that don't target like "Smashing Ground", using "Honest" to destroy it in battle or gain control of it with "Creature Swap" (this method often used in most "X-Saber" or "Gusto" Decks).
This card will be a dead draw if your opponent has "Mask of Restrict" or "Fog King" because they prevent Tributing altogether. So be sure to deal with them first.
A "Battlin' Boxer" Deck can with a little setup take down this card, while inflicting very heavy damage: Summon "Star Cestus" with at least one Material, and use its effect while clashing a "Boxer" with "Obelisk", not only inflicting battle damage, but also negating the effect of "Obelisk" until the end of the turn. During your Main Phase 2, Rank-Up your monster into "Comet Cestus", and use its effect to target and destroy "Obelisk", whose effects would be negated, and inflict 4000 damage, which might end the game. "Rank-Up-Magic Numeron Force" can make this even faster.
If a direct attack from "Obelisk" were to happen (which won't have very pretty results), "Gorz the Emissary of Darkness" can be Summoned or activate "The Golden Apples" which will create a Token powerful enough to destroy "Obelisk".