Step 1. Activate Dragonic Diagram, and use its effect to discard Babycerasaurus and add True King Agnimazud, The Vanisher to your hand
Step 2. Activate Babycerasaurus's effect, special summoning Souleating Oviraptor from the deck
Step 3. Activate Souleating Oviraptor's effect, adding another Babycerasaurus to your hand
Step 4. Normal Summon Babycerasaurus
Step 5. Using Souleating Oviraptor's effect, destroy Babycerasaurus to Special Summon the other Babycerasaurus from the graveyard
Step 6. Using Babycerasaurus's effect, special summon Miscellaneousaurus from the Deck
Step 7. Destroy Babycerasaurus and Miscellaneousaurus to special summon Agnimazud from the hand
Step 8. Using Babycerasaurus's effect, Special Summon Jurrac Aeolo from the deck
Step 9. Synchro Summon Ib The World Chalice Justicar using Jurrac Aeolo and Souleating Oviraptor
Step 10. Using Ib's effect, add World Legacy Monstrocity to your hand
Step 11. Activate World Legacy Monstrocity, Targeting Agnimazud and special summoning Knightmare Incarnation Idlee and a Level 9 Monster
Step 12. Activate Miscellaneousaurus's effect, Banishing two Dinosaur Monsters and itself to Special Summon Giant Rex from the deck
Step 13. Link Summon a link 2 monster using Idlee and Ib
Step 14. Using Ib's effect in graveyard, Special Summon World Legacy Guardragon from the deck
Step 15. Link Summon Guardragon Elpy using World Legacy Guardragon
Step 16. Link Summon Triple Burst Dragon using Giant Rex and the Link 2 Monster
Step 17. Special Summon a Dragon Monster from the deck using Elpy's effect
Step 18. Link Summon Guardragon Agarpain using the Dragon Monster and Triple Burst Dragon
Step 19. Activate Agarpain's effect, Special Summon Hot Red Dragon Archfiend Abyss from the extra deck
Step 20. Link Summon Hierarchic Seal of Heavenly Spheres using Elpy and Agarpain
Step 21. XYZ Summon True king of All Calamities using the Level 9 Monster and Agnimazud