There is a subcategory within anime and manga culture that has an interesting, and even controversial, existence: lolis and shotas. It is a category that pertains to both males and females, portraying either gender as little children, despite them being full-blown adults. Lolis, or girls that have the appearance of being cutesy and prepubescent, are much more common than shotas, which are the male equivalent. They have two aspects of them, one that makes an appearance in normal anime and manga, and the other, which makes an appearance in the genre known as “Not Safe for Work”, or NSFW.
The former aspect, one in which lolis and shotas make appearances in normal anime and manga, are much tamer, but still controversial. They are usually immortal beings, although they can also be eighteen+ year olds, mostly to add comedic humor. Although, it doesn’t help that usually lolis are sexualized, being child-like or innocent in appearance, but scantily clad in small armor. But say they’re a child and they’ll insist that their actually 1000 years old. The biggest example I can think of is the Fire Emblem character Nowi. Nowi is a 1000 year old dragon in scant armor (literal bikini armor with boots and a cape), that looks like she’s 12 years old. It makes romancing her with anyone rather bizarre and kind of uncomfortable, just as it is strange to romance any of the shotas in her game (Ricken and Donnel).
However, this isn’t to say it’s always the case. There are a few lolis that are normally dressed, or dressed in oversized clothes to emphasize their cuteness (the scantily clad nature doesn’t apply to shotas: they are normally dressed from all the cases I’ve seen). Sometimes, the lolis are fully-dressed, making them seem more normal and not sexualized. Usually, though, the loli is dressed in a way that is clearly catering to male fans, and is very much sexualized.
This sexualization plays heavily into the second aspect that lolis and shotas play in: Hentai. Hentai is the anime equivalent of porn, which I mentioned is the NSFW aspect. In this case, lolis and shotas are sexualized alike (of course with the lolis being more common), sometimes being left alone, and sometimes being altered to be more sexual. The lolis especially, will sometimes be given insanely large breasts (we’re talking the length of their body), in order to add some sexuality, while the rest of the appearance stays the same. Shotas are often feminized, too, making them appear as submissive, while the other partner is much more adult-looking and dominant. In either case, both lolis and shotas are most often set as adults. Not all the time, however.
So, how are lolis and shotas ironic? Well, they’re usually adults, with child-like appearances. They insist that they are older, but promote an almost pedophilic image, without explicitly being pedophilic. They encourage a dangerous sexualization of young, prepubescent children, especially young girls, encouraging creepy men (and some women) to check out and even follow young girls. The sexualization pervades in the anime and manga community, tainting its media.