How many monsters did Zeref create in fairy tail?

In the anime and manga series "Fairy Tail," Zeref Dragneel is known for creating various types of monsters, known as "Demons." Throughout the series, the exact number of demons created by Zeref is never explicitly stated. However, several major demons are introduced and play significant roles in the story.

Some of the notable demons created by Zeref include:

1. Etherious Natsu Dragneel (E.N.D.): Natsu Dragneel's alternate persona created by Zeref.

2. The Seven Kin of Purgatory: A group of seven powerful demons who serve Zeref as his elite enforcers.

3. Deliora: A massive and destructive demon that Zeref created in his youth, causing great devastation.

4. Mard Geer Tartaros: The leader of the Dark Guild Tartaros, who is also a demon created by Zeref.

5. Jackal: A powerful demon who possesses the ability to manipulate sand.

6. Seilah: A demon who can transform her body into various weapons.

7. Keyes: A demon who controls lightning and can absorb electricity.

8. Wahl Icht: A demon who can alter his body structure at will.

These are just a few examples of the demons created by Zeref, but their total number is not specified within the series.