Don't know where to begin?

While ultimately it doesn't matter which arc you begin with, Cecil arc is recommended if you want my recommendation.

And then Masu arc + Shattered union arc. 

Feel free to visit the lore section as well which holds stories of its own.

Sae arc (3)

This arc used to be called "Moasic arc".

This is Sae the little witch's story. While there may be only three stories dedicated to her, Sae shows up in a lot of stories as either a bystander or a sidekick.

This arc has been completed.

[Sae arc] [1] [Mosaic Passion] [8711]

Sae… Love or hate her, she’s a nutcase. Though she has her own reasons to be a crazed bitch. This is one of longer stories I wrote. 60 pages. Be prepared.

This story is also very old, probably 15 years old at least based on 2015.

[Sae arc] [2] [Excessive Sleep Syndrome] [96??]

[Sae arc] [3] [Passage of time] [9621]

Mortals hate passage of time.

Immortals hate passage of time as well.