Another way is by showing the desperation of the characters trying to rescue the kidnapped one. If they face numerous obstacles like powerful enemies or difficult terrains, it adds to the tension. For instance, if the Cullens have to fight through an army of new vampires to reach the kidnapped character, the readers will be worried about their success.
One way is through time pressure. The writer could set a deadline for Lupin to rescue the kidnapped person, like if he doesn't do it within 24 hours, something terrible will happen to the victim. Another is by introducing obstacles in Lupin's path. For example, the kidnapper has set up numerous traps and guards around the place where the victim is held. And the writer can also build tension by revealing bits of the kidnapper's plan gradually, making it seem more and more menacing.
By introducing dangerous enemies. In these fanfictions, there could be new, more menacing villains than in the original series. The threat these villains pose to Harry and Hermione, and their plans, keeps the readers on the edge of their seats.
The main reason authors do this is to add drama and suspense. It builds anticipation and makes the reader emotionally invested in the outcome. Also, tension helps drive the plot forward and makes the story more memorable.
By limiting the time. If a Pokemon has only a short amount of time to be saved, it creates immediate tension. For example, if a Pokemon is poisoned and will die in an hour if not treated.
Another way is through the slow development of the relationship. The captor may start off as cold and distant, but as they interact more with the captive, small changes occur. This slow burn while the captive is still in a kidnapped state keeps the reader on edge, wondering when and how the relationship will fully develop into a romantic one.
Authors often create tension through the initial reluctance of the characters. For example, if one character is against the idea of an arranged marriage, there will be conflict. Another way is by introducing external factors like family expectations or cultural differences. This can put pressure on the relationship and create tension.
One way is through the power dynamics. For example, if the male lead is a powerful mob figure and the female lead is an ordinary person, the difference in their status creates immediate tension. He has the power to control her situation, which makes their relationship precarious.
Another way is through the description of Taehyung's own state. If he's in pain but trying to be strong, or if he's confused and hurt by the situation, it makes the readers feel for him. The writers might also introduce some obstacles in his recovery process, like a lack of proper medical facilities or some internal conflicts within the group that delay his getting better. This all serves to create and maintain tension throughout the fanfiction.
Authors create tension by showing the villain's near - successes. When the villain is almost about to achieve their evil goal, like taking over the world or destroying the hero, it makes the readers nervous. For example, if a villain is just one step away from activating a doomsday device, the readers will be on the edge of their seats. Another way is by making the heroes' situation seem dire. If the heroes are outnumbered or outmatched by the villain's forces, it creates tension as the readers wonder how they will overcome the odds.
Footsteps create tension by making the reader wonder who or what is approaching. The mystery builds suspense.