While you have this card as a Pendulum Scale, you can easily swarm the field by Fusion Summoning "D/D/D Flame King Genghis", which would trigger this card's effect and allow you to Special Summon a "D/D" monster in your Graveyard. This would activate the effect of "Genghis" and allow you to Special Summon another "D/D" monster from your Graveyard. You can possibly Special Summon both of the Fusion Materials you fused into "Genghis" with this combo.
Regardless whether it is serving as a Pendulum Scale or a monster, this card has great synergy with the effect of "D/D Nighthowl".
While this card is a Pendulum Scale, Normal Summoning "Nighthowl" and using its effect will trigger this card's Pendulum Effect and allow you to further swarm the field with another "D/D" monster Special Summoned from your Graveyard.
If this card is in the Graveyard, you can Special Summon it with the effect of "Nighthowl" to trigger its own monster effect and Special Summon a "D/D/D" monster from your Graveyard to recover lost advantage and put further pressure on your opponent. Additionally, "Nighthowl" can be Tributed to activate this card's effect to banish a problematic monster your opponent controls.
As the "D/D" archetype contains several Level 7 monsters, you can use the effect of "Transmodify" to send one of them from your side of the field to the Graveyard, then Special Summon this card from your Deck, and immediately use its effect to Special Summon back the monster you sent.
This card can work well with "Dimension Gate", allowing you to use it's monster effect again.
You can initiate a simple OTK in a "D/D" deck if you have this card, "D/D Swirl Slime", and "D/D/D Doom King Armageddon" in your hand. Use the effect of "Swirl Slime" to send itself and "Armageddon" to your Graveyard to Fusion Summon "D/D/D Oracle King d'Arc". Next, use the other effect of "Swirl Slime" to banish itself from the Graveyard and Special Summon this card from your hand. Use this card's effect to Special Summon "Armageddon" from your Graveyard. With this card having 2200 ATK, "Armageddon" having 3000 ATK, and "d'Arc" having 2800 ATK, they have a combined damage output of 8000.
Special summon this card from your scale zone with Pendulum Switch and trigger Ragnarok's effect.