Beast Complex is an anthology drama manga written and illustrated by Paru Itagaki as her debut work. The manga is now better known for being the work from which its author's subsequent Sleeper Hit, Beastars spun out of.

The manga is set in a world where carnivores and herbivores live together, with all the tensions that come from their different instincts. Each chapter focuses on two characters (often a carnivore and a herbivore), going through a specific episode in their lives.

The manga was originally serialized in Weekly Shōnen Champion, starting in March of 2016, where its first five chapters got published. Starting in 2017, Bessatsu Shōnen Magazine became responsible for the serialization of this manga, publishing the last two chapters of its first volume. The manga then came back to being serialized in 2019, with the single 7th chapter, which then continued properly in 2021, starting with the 8th chapter. This second serialization was focused on the Hidden Condo inhabitants introduced in chapter 115 of its Spin-Off, Beastars, but continued even more than those, introducing new characters and even having chapters focused on the aftermath of Beastars. The manga concluded its serialization with its second and third volumes, however the series has not officially ended and Paru considers it to be her life's work; one-shots continue to release sporadically, with her goal to produce 20 volumes of content with an average output of at least 2 chapters a year.

Tropes

• The Alcoholic: Chapter 24 features an alcoholic iguana. He ends up adopting a lost penguin just because it was living in the fridge at the liquor store and getting in the way of them stocking beer because the lazy worker didn't want to deal with it.
• Ambiguously Gay:
  • Chapter 8, "The Pig and the Peacock", features a friendship between the two titular characters which verges very close to romantic territory. Eugen is constantly calling Gerbera the most beautiful thing he has ever seen, and the climax of the story takes place with Gerbera naked in his apartment, after Eugen asked him to pose for him in one of his glass cases. Gerbera even gives Eugen one of his tail feathers as a gift, claiming they aren't useful to him since all they are for is attracting women.
  • Chapter 13, "The Tiger and the Alpaca" has this between the two leads, leaving it up in the air whether the two women have or not had sex.
  • Chapter 20's "The Black Panther and the Sea Otter" also features this between the aforementioned characters Po and Gil, especially with the explicit focus on them holding hands.
• Art Evolution: An exaggerated example due to the series irregular release, but Paru’s roughest pre-Beastars work is clearly visible in Chapters 1-5, with Chapters 6 onward having a notable bump in quality, having all been made either during or after Beastars' run.
• Bad "Bad Acting": Rose is not a particularly good actress, and her rise to getting an award came because her co-star gave an amazing performance that lifted hers. He asks that she plays a role one more time, this time of a person that is as surprised as everyone else to hear of his confession of a crime. When he does, she acts surprised, but her surprised face is comically false.
• Beauty Is Best: Gerbera is a peacock that believes he has nothing to give aside from the beauty of his feathers. Before he is assigned to a more dangerous neighborhood where he believes he will be killed, he begs Eugen to kill him and stuff him so he can stay beautiful as he is now. Eugen manages to talk him down, however.
• Beneath the Mask: In Chapter 15, while investigating why Murou would kill himself, Kameji finds nothing; Murou had no hobbies, skills, or friends, and the front of a mean hyena bully he had is implied to be something he put on because outside of that, he had nothing.
• Bungled Suicide: Chapter 15, "The Python and The Hyena" follows a python named Kameji who is always one of the first people in school coming to his class to find that his bully classmate, a hyena named Murou, hung himself in the classroom. Kameji tries to hide Murou in a panic, afraid he'd be suspected of the crime, by eating him whole, but he eventually spits him out, realizing Murou survived.
• Call-Back: Chapter 18 has the two leads seeing news abou Mugi, the Shiba Inu that led chapter 9, having followed through with his desire to change his image and finding success with his new image of "Handsome Uncle".
• Commonality Connection: Chapter 21 has a White Tiger try to hook up with a Zebra, hoping to find a connection within their similar black and white colorations, tired of how regular tigers tend to other him for his color. His date is unconvinced at first, but a spark does start when he laments that female tigers tend to take black and white pictures of him to obscure his otherness while she notes that zebras actually have a preference for black and white photography to accentuate their stripes.
• Dating Service Disaster: Chapter 21 features a Zebra trying to meet other Zebra on a dating app, only to find her "Zebra" match, who's pictures never show his face, to actually be a White Tiger.
• Did They or Didn't They?:
  • Chapter 13 has an alpaca wrestling a tigress into a position under her on a massage table, the entire thing is framed as if they're about to have sex, but the story cuts right after it, with the tigress simply stating that she can't remember what happened after it, no matter how hard she tries, only that the alpaca's fur felt impossibly fluffy.
  • Chapter 25 has Haru becoming frustrated that her and Legoshi still haven't had sex in 3 years of dating. The story ends with Legoshi embracing her in bed, heavily implying but not outright saying that they might have finally had sex. The volume with the chapter does include an omake panel showing Haru very tired the morning afterward though.
• Does This Remind You of Anything?: The "bright" animals district from chapter 10 is rather reminiscent of a high-control group. It's a closed community whose members are told they are special, and that the outside world is dangerous and out to get them. Orion was being sexually coerced by men in the community, under threat of being revealed as "impure" and cast out into the outside world she was isolated from and taught to fear all her life.
• Driven to Suicide: The plot of Chapter 15 kicks of with Kameji discovering his school bully Murou hung himself in their classroom. While he struggles deciding what to do, he takes some time pondering just what could've driven the hyena to take his own life, eventually realizing that Murou was a Peer-Pressured Bully who used it to mask how empty his life felt. Thankfully it's a Bungled Suicide after all since Kameji got him down before he could actually die from it.
• Early-Bird Cameo:
  • Legosi from Beastars appears at the beginning of the first chapter, taking a nap in the subway the lion from that chapter is taking.
  • Chapter 2 focuses on a young Gon, who would be the headmaster of Cherryton during the run of Beastars.
• Face of a Thug:
  • Bogue from Chapter 7 looks like a crazed bear that is only wearing underwear and drooling from the mouth. That said, it is implied that this is mostly stress from his incoming deadline, as he appears affable if unkept in Beastars.
  • Abu from Chapter 17 is a tortoise that looks like a gangster. He has the word "Hell" tattooed on his shell, and when he isn't retracting his limbs, he is tattooed all over (in Japan, tattoos are associated with criminals). He is actually a pretty nice guy who helps Kiyosumi.
• Fantastic Slur: Tigers call White Tigers "Barcodes" due to their coloration. White Tiger Atari tries to play it off as just a fun little joke between tigers but his date feels like it comes off as a slur.
• Foil: Po and Gil in chapter 20. At work, Po is an impressive key piece in their company's expansion, while Gil is prone to messing up. That said, they both come from very far away to work on the city, Po being a sea creature and Gil being from the countryside, and both experience difficulty to connect with others in this new environment, and sharing their loneliness with each other prompts them to bond over it.
  Gil: It's just I... I've been so overwhelmed lately... I'm lonely and I'm starving.
  Po: Lonely... I hadn't head that word until I came to the land. [...] I've been lonely too, Gil.
• Formula-Breaking Episode: Chapters 14, 16 and 25 mix up the usual format of the series by all featuring Legoshi, the main character of Beastars, as one of the title characters. As a result, these chapters are less like Beast Complex's usual stand alone fare and more like additional epilogue chapters of Beastars, with 25 in particular going even further by being the first chapter of Beast Complex to feature the same two characters a second time.
• Heinous Hyena: Murou the hyena in Chapter 15, who teases and torments Kameji often just for being a snake. It's deconstructed when Murou commits suicide, causing Kameji to wonder if he was secretly forcing himself to be this trope to fit in.
• Idiosyncratic Episode Naming: Each chapter's title is a Name and Name listing the two main characters of the story by species.
• Interspecies Friendship: The series in general explores the bonds formed between its various main characters of different species, ranging from friendship to romantic.
• Interspecies Romance:
  • Chapter 3 focuses on a camel and a wolf, who spend a night together in order for him to understand carnivores better. While their time is short, it's clear that single night and that wolf impacted him deeply, as he lets her eat a bit of his hand.
  • Chapter 6 focuses on the budding romance between a fox and a chameleon.
  • Chapter 10 has an albino crow falling for a kangaroo.
  • Chapter 21 has a white tiger lie about his species on a dating app in order to connect with a zebra.
• Irony: In "The Spotted Deer and the Snow Leopard", two actors have reached the peak of their careers, receiving the in-world equivalent of the Oscar for their performances in a controversial movie called "Dinner". This is also the end of their careers, as Luke, the tiger, is about to confess to a crime on camera. Rose, the actress, mentions how ironic this is.
• Like an Old Married Couple: A point of contention for Haru in Chapter 25 as her relationship with Legoshi has settled into this, which she worried means they’ve become the kind of old couple who doesn’t have sex anymore without ever actually having any sex to begin with.
• One True Love: Chapter 21 explores the concept of a soul mate, at least as it regards to striped animals, who tend to be attracted most to the stripes of other animals, with the common folk belief among them that one's soul mate is one who's stripe pattern perfectly interlock with theirs.
• Scars Are Forever: Chapter 14 shows that scars caused by the claws and fangs of carnivores don't tend to heal, and so superstitions and ceremonies revolve around having the carnivore who inflicted any scars on an herbivore purify them for their coming of age ceremony. This chapter and Chapter 16 also show that most of Legoshi's gunshot related scars have healed, but the claw scar over his eye and across his back still remain even a year after the end of Beastars. By chapter 25, 3 years after the end of Beastars, even the ear he lost in an explosion has fully regrown but the scars remain. Gon receives a scar across his eye in Chapter 2, which he is shown to still have in Beastars, 45 years later.
• Show Within a Show:
  • Chapter 5 goes behind the scenes of show called Happy Happy Cooking whose rating has been declining that brings in a saltwater crocodile to be the show's new host and head chef to revitalize its ratings, to the displeasure of the gazelle sous chef who is terrified of him.
  • Chapter 12 focuses on a couple of actors who just received academy awards for their role in an in-universe movie called "Dinner", which portrays the romance between a carnivore and a herbivore.
• Snakes Are Sinister: Discussed, but averted with the snakes who feature in Chapters 15 and 22. Kameji and Sage are both nice and gentle serpents, if eccentric in certain ways, but both of them acknowledge negative stereotypes associated with snakes that they have to navigate around. The crux of both chapters deals with each of them having the opportunity to embrace a less pleasant aspect of their species — Kameji devouring his seemingly deceased school bully and Sage strangling the life out of a small and defenseless mouse — but both snakes are too kind to do it.
• Stalker Without a Crush / Stalker with a Crush: "The Wolf and the Dog" features a German shepherd named Adamo who stalks random people because of his instinct to follow scents. He is a retired detective who used to track down criminals. He develops a fascination with a female wolf named Fasa, which may have possibly turned into a crush.
• Swallowed Whole: Chapter 15 has Kameji the python struggling to decide what to do when he discovers his classmate committed suicide, and in a panic to hide the body he winds up taking the whole thing down his gullet while passing it off as having eaten a big breakfast. It turns out to be a non-lethal instance of the trope once he realizes his classmate is still alive, and promptly spits him out.
• You Are Not Alone: Chapter 20 focuses a lot on the theme of loneliness. Po and Gil, the protagonists, find themselves painfully lonely in a new city and with nobody to connect with, and end up finding companionship in each other.