This card's primary purpose is to allow the user to recover from an opponent using cards that wipe clean all cards on the field at once, like "Crystal Abundance". However, if you don't mind taking damage, it can also be used simply to get out a strong monster quickly.
This card is ideal to use when in a tight spot to bluff your opponent, for example if you control no cards and your opponent several, and you have only "Sakuretsu Armor" in your hand, but that alone can't protect you if he/she summons another monster, rather than setting it, end your move, even if you haven't "Gorz" in your hand. Your opponent might think you actually have it in your hand, and not dare attack (at least with all of his/her monsters).
If you are trying to activate "Gorz's" effect and don't want a monster on your side of the field, summon a "Neo-Spacian Grand Mole" and send both it and your opponent's monster back to the hands.
A deck centered on "Gorz" should use cards that have effects that are easy to activate and don't have a tough condition (like "Horn of Heaven") so the field can be clear for "Gorz". "Waboku", "Messenger of Peace" and "Dimension Wall" are good examples of cards to use until you draw "Gorz".
When faced with multiple monsters attacking directly, it's important to choose when to summon "Gorz". If your opponent suspects you have "Gorz", they may attack starting with the weakest monsters and work their way up. Summon him when you take little damage and your token can be attacked and destroyed. Wait until the final and most powerful monster attacks and you'll have a powerful token (perhaps even more powerful than "Gorz") and your opponent's monsters won't be able to change to defense mode because they attacked. But this advantage is at the cost of a lot of Life Points, not to mention that it gives your opponent time to either play or set cards that can potentially counter "Gorz" and/or the token you may have summoned. Also, your opponent may choose to not attack with their last (strongest) monster, and repeat this tactic again the next turn.
For this reason, you should consider summoning "Gorz" when you take substansial damage, unless "Gorz" is weaker than your opponent's strongest monster. Your opponent may not attack the token if they have several weak monsters.
Since this token's attribute is LIGHT, it can take the effect of "Honest".
If you know your opponent has "Gorz" in their hand and are pretty sure they won't summon it until your most powerful monster attacks, the following might be a smart move to make. Attack with your weaker monsters first making the opponent anticipate your strongest monster's attack. But don't attack with your most powerful monster and end your turn. Your opponent will be put in a tough spot on their turn if they really need to get "Gorz" out and will have to take damage next turn and/or not commit many cards to the field.
One of the most likely scenarios for the summoning the card is when you have run out of cards on the field to block your opponent's attacks. It only adds to the mayhem because just when your opponent thinks they have the upper hand, you pull back the tide because of "Gorz". This seems the most effective use of "Gorz", even though this method requires taking damage from the last monster that attacked, regardless of the attack of that monster. As such, the token summoned along with "Gorz the Emissary of Darkness" will be weaker than when used as bait for a stronger monster's attack, but at least you have "Gorz the Emissary of Darkness" on the field. Be careful, though. If "Gorz the Emissary of Darkness" is not strong enough to take down the strongest monster on your opponent's side of the field, you will be back where you started.
Even though this card is a DARK Fiend-type monster, it is splashable into any deck as a sort of last-ditch defense.
Both "Gorz" and its summoned token are excellent sources for material monsters in the summon of a level 8 or higher Synchro monster.
"Gorz" is a great top deck after using an effect monster like "Sky Scourge Norleras" or "Gandora the Dragon of Destruction". Even more so for decks based around "Sky Scourge Norleras", as it can be used as material to summon yet another Sky Scourge when it is sent to the graveyard.
If you use "A Feather of the Phoenix" to place "Gorz the Emissary of Darkness" from the Graveyard to the top of your deck, you can activate "Reversal Quiz", and have a 2700 attack Beatstick and the token just waiting to end the duel, since your opponent will likely have very low lifepoints if you guess monster. Since you will have no monsters on the field, and your opponent probably will, they would probably attack you directly. There will be no way you will get it wrong since you placed "Gorz" on the top of the deck.
Summon "Gorz" without the risk of Battle Damage by keeping only an "Enchanted Javelin" on the field and using it when a powerful monster attacks. Because it's activated during the Battle Step rather than the Damage Step, "Enchanted Javelin" will resolve before damage is taken, essentially canceling out damage to your life points, as well as clearing your field before the Damage Step, allowing you to summon "Gorz".
You may use "Sky Scourge Norleras'" effect to clear the whole field and hands, then if you draw "Gorz" with "Norleras'" effect, your opponent shall have to contend with "Gorz's" effect, leaving them with no path to escape.
If you choose to allow a monster to attack you directly in order to summon "Gorz" and bring out an Emissary of Darkness Token, use cards like "Banner of Courage" that boost attack after "Gorz" is summoned, to make the "Emmissary of Darkness Token" stronger than the monster that provided it's Attack and Defense Power. This is particularly effective against monsters that are substantially stronger than "Gorz the Emissary of Darkness" itself, which would allow the Emissary of Darkness Token to attack and destroy monsters such as "Blue-Eyes Ultimate Dragon" without destroying itself in a suicide attack, allowing for the potential for two Beatstick monsters.
You can Tribute "Gorz the Emissary of Darkness" and the Emissary of Darkness Token for a Level 7 or higher monster, which could possibly turn to the Duel around.
If your opponent attacks directly with "Five-Headed Dragon", you can use the token that this card creates to Suicide into it, since the token is LIGHT.
On your next turn, use the Token Special Summoned by this card for "Gift of the Martyr" to power up "Gorz" and launch a counterattack to the Monster that gave you Battle Damage and deal 2700 damage to your opponent (or vice versa), provided neither monsters ATK was altered before it.
Try to Summon "Gorz" when both he and the Token will survive. That way, you can Summon another level 7 (any Dragon Ruler, for example) to overlay "Gorz" and the new level 7 for "Mecha Phantom Beast Dracossack". "Dracossack" will then be safe from cards like "Bottomless Trap Hole" due to your Emissary of Darkness Token, which can either be used to attack/defend while the 2 Mecha Phantom Beast Tokens are Tributed for "Dracossack's" effect.
If you have "Gorz the Emissary of Darkness" on the field, use "Compulsory Evacuation Device" to send it back to your Hand for future use. "Pot of Avarice" also might help return "Gorz the Emissary of Darkness" to your hand or, at the very least, your deck after it has been destroyed.