Isekai Quartet was an extremely ambitious crossover series. In fact, it is the most ambitious crossover in the history of anime, and it’s easy to see why, as it combines characters and settings from four super popular anime series: The Saga of Tanya the Evil, Overlord, Re:Zero − Starting Life in Another World, and KonoSuba. It was sort of the Avengers of the anime world, but with less fighting and a lot more comedy.
The series first aired in April 2019, and it became an instant hit among fans because of its comic timing and its chibi-style animation. Fans were also quick to notice many Easter eggs in the series, which is not a surprise seeing how the anime had four anime worth of materials to reference! For those who missed them, here are 10 hidden details from the anime.
10 Re:Zero Reference
In one of the classroom scenes where Roswaal is teaching his new students, there’s a reference to the anime’s second season where he is reading a book with a completely blackened cover. The book is a nod to the Witch Cult future telling Gospel, which features prominently in its source anime. In the existing anime, it implies that Roswaal is well prepared to catch cheaters before they even cheat.
9 Albedo’s Spell
In season 2 of Isekai Quartet, Albedo uses the “Walls of Jericho” spell in the sixth episode. While doing so, she inadvertently ends up bending the legs of Tanya’s troops. This is a reference to Chris Jericho’s signature “Walls of Jericho” move in WWE.
8 Ainz’s Despair Aura
Although it’s not explained in the original Overlord anime—or even in the Isekai Quartet anime—Ainz’s aura is explained in the light novel. His aura emanates from his robes and not his body.
In some stressful situations, his Despair Aura activates on his own, like when he first met with all the Guardians, but, mostly, it’s completely under his control.
7 Aqua’s Water Powers
Aqua is the Goddess of water, which is why all her spells have a water descriptor. Her spells are actually God tier—pun intended—so much so that they can damage the Undead. But, the reason they’re almost always effective is that she’s not a smart creature, and she ends up fighting monsters that have Water damage immunity, which would mean her spells are ineffective on them.
6 Everyone Has Altered Stats
Isekai Quartet is not a canon anime, so everything in it should be taken with a grain of salt. It’s also the reason why none of the characters in it are as strong or powerful as in their original anime. Most of their stats have been reduced in order to make for a more believable school environment, as well as set the tone for many comedic mishaps.
5 Ainz Studied Up To Middle School
This anime mentions that Ainz’s education ended after elementary school, a detail that even the original Overlord never mentioned. However, fans who’ve read the light novels would know that Ainz actually studied till middle school and went to college in the web novel versions. This is a perfect example of why extra details mentioned in Isekai Quartet should be not taken at their face value.
4 The Dust Explosion
This was a detail that only hardcore Re:Zero fans would have noticed, if at all. In one of his many classes, Roswaal is seen teaching his students about dust explosions, which is a nod to what happens in the original anime. Subaru and his group of friends enter Roswaal’s room, where Subraru tries—but fails—to finish the Demon Beast off with a dust explosion.
3 When Kazuma Thinks Subaru’s World Is Easier
Kazuma and Subaru are two of the most famous protagonists from the Isekai genre, so fans loved it when the two not only met each other but discussed whose world would be easier to live in.
Subaru believes there’s less danger in Kazuma’s world, while Kazuma angrily states that it is Subaru’s world where living and growing old would be a piece of cake. Fans still argue to this day as to whose Isekai world is tougher to survive in.
2 Ainz’s And Tanya’s First Meeting
Initially, Ainz believes Tanya to be exactly like him, someone who lets his subordinates walk all over him in order to avoid any confrontations. But, the more the two talk to each other, the more Ainz realizes that Tanya possesses true leadership qualities, something that he severely lacked. Not surprising, considering Ainz was actually a salaryman in real life, while Tanya was… Tanya.
1 Cocytus’ Breath
In the scene above, Subaru is later seen shivering when Cocytus’ breath touches him. Most fans believe it to be steam, but that’s physically impossible for a being like Cocytus. Steam is hot, while his breath was actually a frosty mist. He comes from an extremely cold world, and he’s even named after a frozen lake in the ninth layer of hell!
Isekai Quartet may come across as a superfluous, non-canon crossover series, but here are 10 details hidden in the anime that fans may have missed.