With the right sequence, its completely possible to attach two or even three Energy to Mega Rayquaza during a single turn, allowing you to threaten massive knockouts much earlier than your opponent expects
By discarding "Atlantean Heavy Infantry", "Atlantean Marksman" or "Atlantean Dragoons", to activate the "Mermails" effects you can destroy a card on the field ("Heavy Infantry" and "Marksman") or search your Deck for any Sea Serpent monster ("Dragoons"), such as "Abyssmegalo", while also gaining the "Mermail" effects
PAIN FOR ALL Hello somewhat better Arcbond
This combo is one of the most consistent win conditions in the format and fits well into decks like Jeska/Thrasios, Kraum/Tymna, and other fast shells
For instance, Cabal Paladin deals 2 damage for every historic spell cast, such as Artifacts