Incest is illegal in real life. But to my knowledge depictions of it such as stories or movies are not widely illegal, although they seem to be frowned up. Just look at Patreon. A lot of this seems to be because incest is viewed as rape. Depictions of rape also aren't illegal in most places that I am aware of, but are also frowned upon.Research by the moderators? 3rd party patch?
It's simple. If you want Ada to be 18, don't marry her. If you don't want any Ada scenes, don't play with the patch, or don't go after her.
I find it funny that people are worried about Ada's age being illegal, when nobody talks about incest being illegal.
Cartoon depictions of underage characters are directly illegal in many countries. There is a huge difference between the two. If incest depictions are illegal in your country, then you knew the risks before downloading and installing the patch. You didn't know about the age thing though until you came across it and realized you had illegal content on your computer. Yes, people here pirate games, but it's not likely to put them in prison. And the act of piracy alone is not going to get them labeled as a sex offender. Viewing a character that looks young but is defined as adult is less likely to get them in trouble than one that is clearly defined as underage, but it varies from country to country, and sometimes by region within a country.