Tagami Tatsuya has an ambition of world conquest and the first step of his plan is to make every one of his female classmates pregnant.

What are the best anime to 'convert' someone?

If they like Mind Games, then Death Note or Erased. If they like Violent shows, then maybe Assassination Classroom, Angel Beats, Akame Ga Kill, or Psycho Pass listed in order of least to most violent(honestly, it is debatable whether Akame Ga Kill or Psycho Pass is more violent, I just put Psycho Pass last since it has more “realistic” violence, but enough people in Akame Ga Kill die to call it a tragedy anime). If they like horrific gore for the sake of gore, there are actually a few options, such as Another, Corpse Party, and Tokyo Ghoul(I am not putting a picture of Corpse Party on here due to the vulgarity and low quality of it, also, don’t recommend it to a newcomer). If they like Sci-Fi shows, then Psycho Pass, Steins Gate, The Irregular at Magic High School(would not recommend recommending), a Certain Scientific Railgun(would not recommend recommending), or Fullmetal Alchemist may please them. If they like Mystery, then perhaps Monster, Hyouka, Detective School Q, or Detective Conan would please them. If they like Survival Games, then the Future Diaries, Danganronpa, or Deadman Wonderland may please them. If they like Societal Commentry, then My Teen Romantic Comedy, the Saga of Tanya the Evil, or Death Parade may please them. If they like some Competition, then I have No Game No Life(actually, although this is a good anime, don’t recommend it to a newcomer), Ben-To(actually, although this fits this category extremely well, don’t recommend it to a newcomer), and Boku No Hero Academia. If they like Tragedy, then Your Lie in April and Clannad(specifically after watching the sequel). If they like lighthearted happiness, then I have them covered as well.
Try Love, Chunibyo & Other Delusions, GJ-Bu(this treads into Harem territory, but it is absolutely not a harem anime), New Game!, the Pet Girl of Sakurasou, Baka and Test - Summon the Beasts, My Love Story!!, Clannad(specifically without the sequel), and I Can’t Understand What My Husband is Saying. On a side note, I would also recommend One Punch Man(comedy with death of villains and classism), Durarara(a really entertaining story), Charlotte(an amazing story), and Beyond the Boundary(a love story with some drama), since they don’t fit exactly in any of these categories.