A 'historia visual novel' could be about various things. It might be a story set in a historical context, with characters and plots that unfold in a way typical of visual novels. It could focus on a particular era, like the Renaissance or the Victorian age, and tell a fictional story with elements of that time's culture, society, and events.
Reiner did die in the manga. His death was a result of a series of events and conflicts that had been building up throughout the storyline. It had a major impact on the plot and the other characters.
There could be some, but it really depends on the market and the fan base. Since visual novels are a diverse genre, those with a historical focus might not always get the same level of mainstream attention. But in the communities dedicated to visual novels and historical fiction, there may be some well - known 'historia visual novel' titles that are highly regarded for their storytelling, art, and historical accuracy.
There could be. Check out various fanfiction communities. They often have filters or tags that can help you find the more family - appropriate stories about Eren and Historia in this situation. It may take some searching, but they do exist.
Love and sacrifice are common themes. Often, Reiner has to sacrifice something for the sake of love in these fanfictions. It could be his position in the Legends world or his own safety.