Omake no Tensei-sha

Aihara Runa was a person who had been living in hell of misfortune. One day she found herself in a strange stage, apparently her soul was reaped without permission and sold at an auction to gods from another world along with her 28 classmates. But there was a trouble, it seems that Aihara's soul was extremely smelly and stinky. Instead of getting a buyer, she was thrown away and with her soul in danger of disappearing.

However, when her soul was about disappear, she met an unnamed goddess who claimed herself as a god's vessel. The goddess said that she can help Aihara to get reincarnated but with one condition, that is to bring her along and get reincarnated together. Aihara who was about disappeared accepted the goddess' condition and got reincarnated successfully as Emmy. But apparently, the hard life still continued even after reincarnated too....

If there's no food, then let's get some bugs!!! Let's just enjoy this hard life together with the reliable partner [Omake-sama] inside my head and have fun instead.

As Emmy managed to survive while watching and getting involved in the events of another cheat reincarnations, she grew into an irregular. This is a story about Emmy, a soul who managed to survive from disposal by gods. However, she doesn't know that her reincarnation did not list in fate's archive and unconsciously broke the gods' scenario one after another.

(MTL Translation starts at chapter 85, picture & story not mine, for offline purposes and to promote this good book to other lazy readers who don't like to translate Raws like me)