Sam Serra was your typical loser. But somehow, he caught the attention of the most popular and gorgeous girl in school, which ultimately caused his death.
He reincarnated in a new world, but a world of sword and sorcery. Being a reader of fantasy novels, he realized that he was in one. However, the rules of the world applied to him differently.
For one, he did not have the same abilities as the local people, who cultivated special abilities according to the skills they were born with. Instead he found himself choosing skills like in a game, with typical D&D skills.
However, as he chose to be a mage, he found that the spells he chose did not work the way he expected.
For example, one of his skills is to summon familiars. But as the world and game system had no reference to summon any familiars, it summoned instead characters from movies or TV shows that he had watched.
But in order to summon familiars, the game system was unsure of how to do so, so it searched the only way humans could procreate.... sex.
And that was one of the many differences in how his skills would work.
Not only did Sam now have a tremendous advantage in this world, but due to the differences in understanding by the game system, his time in the world would not be as straightforwards as expected.