Every Easter Egg In Isekai Quartet! Subtle OVERLORD, KONOSUBA, RE:Zero & YOUJO SENKI References

As one of the most ambitious crossovers in anime history, Isekai Quartet goes a long way to not only bring out humor that can only be found through the interaction of all these unique characters. But to also delve deep into their individual lore and personal stories. From this comes plenty of little Easter Eggs that serve as subtle references to the root series of each character.

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Re: Zero Cut Content:
Episode 1:    • Re:Zero Cut Content: What Did The Ani...  
Episode 2 - 3:    • Re:ZERO Cut Content: What Did The Dir...  

Overlord Vids:
Cocytus:
Part 1:    • Who Is Cocytus? | OVERLORD - The Inse...  
Part 2:    • Who Is Cocytus Part 2 | OVERLORD Cocy...  
Part 3:    • How Strong Is Cocytus? | OVERLORD Coc...  
Part 4:    • How Strong Is Cocytus? OVERLORD | Eve...  

Aura & Mare:
Final:    • What Are Aura & Mare’s True Combat Po...  
Who Are Aura & Mare:    • Who Are Aura & Mare? | OVERLORD - The...  
How Strong Is Mare:    • How Strong Are Mare & Aura? | OVERLOR...  
How Strong Is Aura:    • How Strong Is Aura? | OVERLORD Aura's...  

You know what... Here's the playlist:    • Overlord Explained