What are Chubby Lungs and How Did They Get All the Way to Anime Expo?

I first learned about Chubby Lungs in an Anime Expo press email. In it, the development team at Hypergryph highlighted mini-games featuring the Lungs as part of the Arknights: Endfield booth at this year's convention. I didn’t know these bean-shaped dragons had a specific name, even though I’d seen them in passing on the Wuling map.

I played Arknights: Endfield at launch and its multiple demos in the past, never quite getting to the point of delving into Chubby Lungs and their history. So, I set out to change that by actually visiting the Arknights: Endfield booth at Anime Expo 2026.

My experience at the Anime Expo booth

Chubby Lungs are easy to conceptually understand if you know what a “Lung” is in Arknights. The world of Arknights (and Endfield by extension) features many humanoid races with animalistic features like cat ears and horns. Lungs, likely coming from the Chinese word for dragon, are based on Eastern dragons and have thin, pointy horns and serpentine tails. Operator Chen Qianyu, one of the first characters to join your party in Arknights: Endfield, is a Lung.

Chubby Lung basketball and curling games were just part of the carnival of Endfield-themed activities at Anime Expo. What I found at the convention was an elaborate display decorated with Arknights’ futuristic aesthetic, bright promotional banners featuring popular characters, and replicas of in-game landmarks like Tele-Protocol (TP) Points (fast-travel points that could heal and connect with your depot) and Protocol Dataloggers (a.k.a. “wavy tube men”). 

Other highlights included a boxing game inspired by operator Mi Fu and her martial arts-inspired fighting style, photo opportunities with professional cosplayers dressed as the main characters, and an on-site store for fans to buy Arknights: Endfield branded merch. (I missed the Arknights: Endfield Reflective Folding Umbrella, which was in high-demand with that sky-high UV index that weekend!)

As intended, I played the Chubby Lung mini-games. The booth featured two branded basketball machines with Chubby Lung plush toys as the “balls,” which I then had to throw into a basket like I would in an arcade game. There were two Chubby Lung designs, one smiling, relaxed Chubby Lung and one frowning, more serious Chubby Lung (more on that later). 

The curling game featured the same Chubby Lung designs, just as handles on a puck rather than balls. Curling (the sport) uses large granite pucks instead of small ones like the kind in the mini-game, but it’s all about inspiration. Similar to the real game, the goal was to slide a Chubby Lung puck across a long board toward a target at the end. The closer the puck is to the center, the higher the score. 

These games were a more engaging way to experience the fanfare surrounding Arknights: Endfield rather than just flyers and merch. However, it just made me more curious about the development team’s involvement with the booth and how Chubby Lungs became a big enough deal to make it all the way to Anime Expo. Shortly after visiting, I followed up with the team to ask about their vision with the Chubby Lung mini games and the origin of Chubby Lungs for funsies. 

In regards to the mini games, they replied, “Their round and cute shape makes them really easy to imagine as part of simple, playful mini-games, and basketball and tabletop curling are both activities that are easy for visitors to understand and join in on at a booth. When we were designing the booth activities, we thought it would be really adorable to turn Chubby Lungs into basketballs and curling pucks.”

“More importantly, we didn't want the booth experience to just be about lining up, checking in, and receiving freebies. We wanted visitors to have something more interactive and entertaining to do, while still making sure the activities felt connected to the game rather than added on randomly. Chubby Lungs were a great fit for that, as they helped make the mini-games feel more fun, more visual, and more connected to Endfield.”

This made sense, considering there are only so many round, memorably cute objects in Arknights: Endfield. It would be difficult to play sports-based mini-games with a non-round object. I couldn’t deny that it was easy for me to pick up as well, even as I raced around the booth to try the games without disturbing other guests. 

Also, they mentioned, “We also had this fun image in mind of the Zhuang Fangyi cosplayer holding a Chubby Lung basketball for photos, since in the game, Zhuang Fangyi is known for liking Chubby Lungs as well.”

Zhuang Fangyi is Arknights: Endfield’s resident Chubby Lung fanatic. She was released as a 6-star operator in version 1.2 nearly three months before Anime Expo and introduced in the second region of Wuling, where Chubby Lungs appear in Endfield. Funnily enough, even though she loves Chubby Lungs, she is actually a Kylin and not a Lung. (Kylins are based on qilins, a Chinese mythological creature that has the top of a dragon and bottom of a goat. For reference, another popular qilin-inspired character is Ganyu from Genshin Impact.)

On the meaning and design behind Chubby Lungs

The developers also explained to me the artistic advantages of Chubby Lungs, specifically how their round shape could be used as an easily customizable base for multiple types of characters (more than one creature or archetype). Besides being cute, the roundness of Chubby Lungs also has meaning in Chinese culture.

“When designing mascot-like characters such as Chubby Lungs, the team did not want to limit them completely to one specific traditional creature or fixed character archetype. Instead, we wanted to give them a more flexible and expandable visual language,” developers told RPG Site via email. “A rounded base shape makes it easy to add different features and components, allowing more variations to be created while keeping the overall impression lighthearted, fun, and approachable.”

“At the same time, round shapes also carry a sense of "reunion" in Chinese culture,” developers said. “In Arknights, we often release festive content around Spring Festival, so this rounded, cute, mascot-like design also fits well with the feeling of gathering together and welcoming a new year.”

Chubby Lungs didn’t have an official name for some time. The first bean-shaped Lung designs appeared in Arknights to represent the Sui siblings, and because of their shape, the community largely referred to them as “Beans.” 

Chubby Lungs didn’t represent a single character, but multiple. However, when asked about the design for the Chubby Lungs seen in Arknights: Endfield, developers referenced Fangxing Avenue, a commercial district in Wuling, rather than a particular person.

In regards to Wuling, “We felt that it really needed a "mascot": something cute and friendly, something that could carry the "past" inherited from Yan while also representing the "present " and "future " embodied by the idea of Tianshi being part of everyday life. With that in mind, creating a Chubby Lung felt like a very natural answer, and we quickly settled on that overall direction.”
 
The team also told the story of how they decided on two Chubby Lung designs, the same ones featured in the basketball and curling activities at Anime Expo. 

“From there, we continued brainstorming around Wuling's early concept of "a city of Tianshi and a city of learning." In the end, we made a special decision: why not make two of them? Starting from the idea that Tianshi should be both scholarly and martial, we designed one relaxed and cheerful "Pen" Chubby Lung, and one disciplined and serious "Blade" Chubby Lung.”

The Pen and Blade Chubby Lungs are colored white and green respectively. As seen in photos, the white one has a mischievous w-shaped smile (e.g. uwu) and the green one has a more grumpy “upside down v” type (e.g. :<) of mouth. 

“This not only matched the spirit of Wuling, but also gave the two mascots a fun sense of contrast, almost like a pair of friendly rivals or close partners. From there, many road signs, safety notices, and friendly reminders naturally followed,” developers said. “As the design developed further, the Chubby Lungs were no longer limited to Fangxing Avenue. We began using them throughout different corners of Wuling, and they gradually evolved from street mascots into "life ambassadors" for the entire city.”

On popularity and demand for Chubby Lungs

It’s the first time we’re seeing Chubby Lungs at a convention like Anime Expo. However, fans were able to buy them as merchandise way before that. Gryphline started making Chubby Lung plushies after they’d been a community meme for some time and the official Gryphline store still has a limited-edition Chubby Lung t-shirts and  display pieces for sale.

I asked an Arknights representative why they hadn’t brought Chubby Lung plushies to the con, and they replied that it was because demand was so high that they were currently sold out. (Even now, a brief Google search confirms that–at least, from the U.S. market. Your best bet is to wait for restocks on online marketplaces like ACGGO or pop-up markets.)

Developers noted that, while they hoped players would like Chubby Lungs, the level of enthusiasm was “beyond what [they] originally expected.” The community further nurtured the original vision for Chubby Lungs with their own creations. 

“Many players created their own Chubby Lung illustrations, memes, and other fan works, and those creations also gave us inspiration. They helped us see the vitality and potential of this image.”

They added, “At the same time, while Chubby Lungs have become very popular, we also know that many players are looking forward to seeing us explore new mascot-like designs and new visual series. So as we continue expanding Chubby Lungs and related designs, we are also creating other types of characters and mascots, hoping to bring players more fresh and different experiences.”

This didn’t surprise me, considering how common it is for developers to create mascot representations of their characters. For example, Honkai: Star Rail even has “cake cats” related to the character Ruan Mei and her experiments. These cats have an uncanny resemblance to HSR characters, much like the Chubby Lungs reminiscent of Arknights’ Sui siblings. The developers’ response also highlights that Chubby Lungs may have competition as the fan-favorite Arknights mascot representation because of other ideas they have for the future.

The team couldn’t confirm any other Chubby Lung-related events coming up, but they did say this:

“For future plans, we cannot talk about anything that hasn't been announced yet, but we do hear the feedback from our community. If there are chances where Chubby Lungs fit naturally with the theme or format of an event, we would definitely love to explore more ways to bring them into the experience, whether that's through booth design, decorations, or fun little interactive activities.”

That’s neither a yes or no. There are no Chubby Lung-related events in the latest 1.4 update, but we’ll see what happens beyond that.