One element is the lyrics. If the lyrics are about dark topics like death, ghosts, or curses, it can be scary. For example, lyrics that describe a spooky encounter with a supernatural being. Another is the tone of the rap. A slow, deep, and menacing tone can add to the scariness. Also, the setting where the rap takes place. If it's in an abandoned place like an old factory or a haunted house, it gives a creepy vibe.
Mikasa and Eren don't kiss in the manga. The focus of their connection lies in different aspects of their shared experiences and the evolving plot rather than a romantic kiss.
Well, here's one. In a small town, there was a rap battle. A young rapper named Jay took part. He rapped some really bold lyrics. But after the battle, he started having nightmares. In his dreams, he was in a dark room and a shadowy figure was rapping at him, criticizing his skills. Every night the dream got worse, and the figure got closer. One day, he decided to stop rapping, and the nightmares finally ceased.
I'm not sure. It could vary depending on the plot development and character arcs. You'll have to look closely within the light novel to get the exact moment.