Often, they start with the main character in a normal, everyday situation. For example, in 'Re:Zero', Subaru is just an ordinary guy going about his day in a modern - day setting. Then suddenly, something strange happens like a magical portal or a mysterious force that transports him to another world. In 'Steins; Gate', it begins with Okabe's seemingly normal life as a self - proclaimed mad scientist, until he discovers a way to send messages to the past, which is the start of his journey into a different kind of 'world' in terms of time - travel and altered events.
Many isekai visual novels start with the protagonist being dissatisfied with their current life. Take 'Konosuba' for example. Kazuma is a NEET who dies in a rather comical way and then is sent to a fantasy world. This dissatisfaction or some kind of disruption in their normal life serves as a trigger for the isekai element to kick in. Another common way is through a summoning ritual. In some novels, the main character is summoned to another world by magic - users who need their help or for some other purpose.
Isekai visual novels may start with a sense of mystery. For instance, in 'Zero Escape: Virtue's Last Reward', the characters wake up in an unknown location that is clearly not the world they are used to. There's a feeling of being trapped and having to figure out what's going on. Or, it could start with a dream - like sequence that then transitions into the real isekai situation. In some cases, the character might be exploring an old, abandoned place and accidentally stumble upon a gateway to another world, like in some less - known isekai visual novels where the discovery of a strange object or place is the start of the adventure.
Most isekai novels start with the protagonist being transported to another world. This could be due to death, a magical spell, or some sort of strange phenomenon.
Often, they start with the main character being transported to another world. This can happen in various ways. For example, they might die in their original world and then be reincarnated in a new one, like in 'Re:Zero'. Or they could be summoned by some magic or a powerful entity, such as in 'The Rising of the Shield Hero'.
The opening of a fantasy novel usually had many different ways of writing because the theme and plot of a fantasy novel were very diverse. It was necessary to design the opening according to different plots and topics. However, generally speaking, the beginning of a fantasy novel would involve a mysterious scene or character to arouse the interest and curiosity of the readers. Then, they would introduce the background story of the character or scene or show some mysterious symbols or items to lead to the next plot. The beginning of a fantasy novel would often describe the character's personality and mentality so that the reader could better understand the relationship between the characters and the emotional changes in the story. In the beginning of a fantasy novel, creativity and imagination were very important because the readers had already decided their views and comments on the novel at the beginning. Therefore, many authors would show their imagination and creative ability in the beginning to let the readers feel the unique style and charm of the novel.
Often, advent novels start with the introduction of the main character in their ordinary life. For example, in 'The Hobbit', we first meet Bilbo Baggins in his comfortable hobbit - hole, going about his normal, uneventful daily routine. This gives a contrast to the adventure that is about to unfold.
Often, zombie novels start with a mysterious outbreak or event that turns people into zombies. Maybe it's a virus or a strange experiment gone wrong.
They develop by having the protagonist gain power or status in the new world. This attracts female characters. In 'No Game No Life', Sora and Shiro enter a different world and their intelligence and unique abilities lead to them having a group of female followers. The plot also involves challenges and competitions that further the relationships in the harem.
Typically, 'isekai gamer fanfic' start with the main character being transported to another world. Then, they use their gaming knowledge and skills to survive. For example, they might know how to level up fast or identify rare items. Next, they often face challenges like fighting monsters or dealing with political intrigue in the new world. As the story progresses, they grow in power and influence in that world.
Typically, these novels begin by introducing the character in a familiar world. In 'The Wizard of Oz', Dorothy is at home on the farm. Then, a natural or supernatural event occurs. It could be a cyclone in Dorothy's case, which whisks her away to the new world. This allows the reader to relate to the character's initial state before being plunged into the unknown and magical realm of the portal fantasy.
Often, they start by introducing a mystery or a strange event. For example, in 'Raise the Titanic!', it might start with some strange discovery related to the Titanic that sets the whole adventure in motion.
Often, they start with the summoning event itself. For example, in 'That Time I Got Reincarnated as a Slime', the main character is stabbed and then suddenly finds himself in a new world, which is a form of summoning. It's a quick and unexpected start that throws the character into a whole new situation right away.