I think such themes are often related to adult and explicit content, which is not suitable for general discussion.
I think it's often related to themes of power, control, and sometimes taboo exploration. But such content may be inappropriate or controversial.
Common themes could be about forbidden desires and the thrill of multiple partners. But keep in mind that this kind of manga is highly specialized and may not appeal to everyone due to its explicit nature.
Often, such manhwa might explore themes of extreme fantasy or taboo. But it's a rather niche and not mainstream topic.
In general, such extreme and potentially offensive themes like girls and double anal are not typical in manga. Manga usually deal with various genres like fantasy, adventure, and slice of life with more positive and engaging content.
Common themes in such works often include the exploration of morality and ethics, the impact of supernatural powers on characters' lives, and the struggle against inner demons. Another common one is the idea of finding a balance between the human and demonic sides within a character.
Well, love and sacrifice are often common. Mothers in these works usually show deep love for their children and are willing to make big sacrifices for them.
One of the common themes is the exploration of technology and its impact on society. Another could be the internal struggles of the characters dealing with the responsibility that comes with controlling such powerful machines. Also, themes of teamwork and self-discovery are quite prevalent.
Friendship and adventure are often big ones. You'll see characters growing and learning through their experiences together.