Dieter

 specializes in Fire attacks and defensive abilities to enhance the protection of their Geneticists.

Abilities
is the fastest homunculus to level due to good area of effect homunculus skills and the fire element is good in most places. It is probably the most popular Homunculus S. However, it has very bad ASPD after mutation, making leveling painful until Lava Slide is unlocked. Can be alleviated slightly if its base was a Vanilmirth or Filir.

Trivia

 * Dieter is a German given name, a short form of Dietrich.