Unlike its previous two forms, "Yubel - The Ultimate Nightmare" can activate its effect any time it battles. It does not need to be attacked first.
Use "Lava Golem" or "Grinder Golem" to give your opponent a strong monster, then use this card to destroy it and do 3000 damage.
Send "Destiny HERO - Departed" to your graveyard and you can continuously revive him on your opponent's side of the field to give "Yubel - The Ultimate Nightmare" a monster to attack. As Departed is destroyed by "Yubel's" effect it will go back to your graveyard instead of being banished.
Equip this card with "Heart of Clear Water" to help protect it from Spell and Trap cards and monster effects that designate a target to destroy.
Using this card for "Montage Dragon's" effect will give 3600 ATK. Using three of this card will give "Montage Dragon" 10800 ATK.
Unlike previous forms of "Yubel", this card is vulnerable to card effects removing it from the field. "Dark Illusion" might be worthy cards to prolong the life of your "Yubel - The Ultimate Nightmare".
This card's effect works best with "Phantom of Chaos" if it battles an opponent's monster while in attack position since no battle damage is involved and the battled monster is destroyed at the end of damage step.
Synchro Summon "Red Nova Dragon" and then give it to your opponent with "Creature Swap". Then attack him every turn with "Yubel - The Ultimate Nightmare". Your opponent gets 3500+ damage, but "Red Nova Dragon" isn't destroyed due to its own effect, leading to theoretically 3500+ effect damage per turn.
Use it with "DNA Surgery" and "Diffusion Wave-Motion". "Yubel - The Ultimate Nightmare" is able to attack all monsters your opponent controls this turn and destroy them with his effect.
Trigger Nightmare Archfiends during this to give your opponent its tokens. Each will deal 2000 on destruction + 800 due to their effect, totaling 8400. A very abrupt One Turn Kill.
If the DNA + Diffusion combo isn't available, you can force the tokens to attack "Yubel - The Ultimate Nightmare" with cards like those listed above ("Staunch Defender", "Battle Mania", etc.) for the same result.
Combining the Yubels with "Brionac, Dragon of the Ice Barrier" allows you to control which form of "Yubel" you have on the field (provided that you have at least 1 card in your hand for costs). Use "Limit Reverse" or "Call of the Haunted" to summon "Yubel". Then, send the revival card back to your hand to destroy her, Special Summon "Yubel - Terror Incarnate", and send "Terror" back to your hand to summon "Yubel - The Ultimate Nightmare". Then, you can even use the "Yubel" form in your hand as a cost to send an opponent's card from their field to his/her hand.
This card is a good choice to use with "Last Turn" due to the fact it cannot be destroyed by battle and that it destroys whatever card it battles means that in most cases it will ensure at least a draw, if not victory.