Lighter

He dons a long, tattered red scarf that lights ablaze when he uses his fire-based techniques. His right arm is equipped with a gauntlet that wreaths his punches in flames. A Bobber-style motorcycle with a Boxer Twin engine.

The Sons of Calydon live out in the wild, desert lands of the Old Oil Fields, where oil and gasoline matter more than life. Running oil and gas around the desert and to other local areas is what helps drum up money for the gang. This also leads to Lighter, and her crew having to fight other biker gangs.

Hollows are an apocalyptic-level disaster, an abnormal spherical dimension that appears out of thin air swallowing everything they touch. The internal space-time environment becomes disorderly due to unknown influences, and dangerous mutant creatures known as the "Ethereal" are produced. Ordinary people lost in the Hollows face not only the horror of being attacked by monsters, but have to risk the corruption and eventual mutation. Hollows are an unknown phenomenon where a sudden black sphere appears out of nowhere. These Hollows swallow everything unfortunate enough to be in their path. While Hollows can appear spontaneously, they usually give a sign before appearing, such as vibrations in the surrounding area, electrical malfunctions, and certain objects disappearing from their initial place and reappearing in a completely different location.

Once swallowed, both non-living and living beings inside the Hollow will be subject to Corruption. Non-living objects will form Ether crystals. The deeper the part of the Hollow, the higher the concentration of Etheric energy in that place, which can accelerate the corruption and increases Pressure.

For humans, the time before corruption takes a toll on their body depends on their Ether Aptitude and equipment. Some people have high Ether aptitude, allowing them to explore Hollows for extended periods without suffering the effects of Corruption. Those with low aptitude can still explore Hollows by wearing Anti-Ether Corruption equipment, which is commonly used by PUBSEC officers, Jaegers soldiers, and thugs. If a human is corrupted, they will turn into an Ethereal.

Intelligent machines can also be corrupted if they have passed the Forbidden Fruit test.

Once inside the Hollow, everything appears normal, with the same weather as outside the Hollow. However, everything inside is shifted by the Hollow's fissures, turning it into a maze with layers of distorted places. What seems like a dead end can be a way out of the Hollow or an entrance to a deeper part. The deeper the Hollow, the higher the concentration of Etheric energy, which accelerates Ether corruption and attracts swarms of monsters.

Hollows also seem to be interconnected with each other, as passing through a Fissure may lead to an entirely different Hollow, included Hollow Zero.

Hollows are naturally complex places to explore, and being careless can lead to death for inexperienced and experienced explorers alike. To safely explore Hollows, many explorers bring Bangboo with them. These Bangboo are equipped with the Carrot program, which guides explorers along safer paths, minimizing the chance of falling into the deeper parts of the Hollow.

Hollows are a natural source of Etheric energy, which has been successfully harnessed by the people of the new era as a new energy source. This method involves placing a pipe network underneath the Hollow. The pipes absorb Etheric energy produced by the Hollow, which is then converted into usable energy. After the Etheric energy is converted, the leftover Ether corruption is released into the air through "Shiyu". This method is very efficient for obtaining Ether energy while also preventing the Hollow from expanding further.

Hollows are sustained by the Ether energy inside them, and for many Hollows the amount of Ether energy is sustained by the Ethereals within them. It is possible to reduce the size of a Hollow by destroying a massive number of Ethereals, or eliminating a particularly large one. Killing enough Ethereals can even allow a Hollow to be completely eliminated, and once suppressed a Hollow will gradually shrink until it disappears.

Susie: It's been a while, Lighter. Here to buy some music toys? I'd suggest these ones. They're all beautifully made! Lighter: Thanks, but I don't really have any use for those ones. Susie: Huh, no use for them? That's a strange way to put it, they're just decorations. Oh, I get it — they don't match the color of your display cabinet, right? Susie: You seem like a pretty relaxed guy — but you actually have a serious side huh? Lighter: Haha, you can think that. Lighter: Excuse me, Miss. Could you please grab the models and quantities from this here shopping list? Susie: Of course! Let's have a look... You're buying a lot of the same model! Susie: It's just like my boss always says, "If there's something you really love, always buy three. That way you'll have one to use, one to keep, and one to share!" Lighter: Haha, you can think that. Susie: Why do I feel like you're dodging my questions? Have I guessed completely wrong? But it's okay, it's like my boss says, "No one can truly understand others, or even themselves." Susie: I'll get the items for you. Come on over to the store with me!

Excited Schoolgirl: Whoa, you're the famous podcaster "Lonesome Traveler", aren't you? You're even more handsome in real life! Lighter: Huh? Um... thanks. Excited Schoolgirl: Umm, I'm one of your fans. Could I please... shake your hand? Lighter: Sure, no problem. Excited Schoolgirl: Wow... You're so nice! Uhh, I heard you're plannlng to enter the entertainment industry. You can do it! I'll always support you!

Piper: Hey, Lighter~ I really couldn't care less about your private life... but is that true about you having a side hustle as a podcaster? Lighter: Huh? What are you talking about, Piper? Of course not. Piper: No no no, I think it's very possible~ Didn't you say you'd consider any work so long as it pays. And there's lots of people making decent money from it nowadays~ Lighter: Are you saying it's a better option than staying in the Sons of Calydon? I'll have to think about that. Piper: ... Lighter: I'm just kidding. Piper: Why didn't you just tell her she had the wrong person, instead of shaking her hand? Lighter: She was so happy. I'd rather leave her in a good mood than disappoint or make her feel awkward. Piper: sigh I never thought I'd hear such uplifting words from someone so young!