Overlord Twitter Side Story is a non-canon side story written by Maruyama Kugane. The story was posted on Maruyama's Twitter account on September 26, 2015.
Main Summary
This side story from the author tells a different turn of events of the protagonist. Momonga enjoying the last hours of YGGDRASIL, decides to spend his time outside of the Great Tomb of Nazrick. Upon exiting the tomb, he finds himself in a new world and meets an unexpected character.
Full Summary
Momonga having enough of sitting idly by as YGGDRASIL is permanently shutdown makes the decision to celebrate the end of the game in style.
He heads towards the surface teleporting through various rooms using the Ring of Ainz Ooal Gown. He flies off to a small little island in the Grenbera Swamp and sets up 5000 fireworks to explode and burst into the sky. While blinded by the brilliant flash of light, Momonga notices that his surroundings have changed from a swamp to a ruin.
Unable to determine his situation and exact location, Momonga decides to patiently explore his new surrounding. To gather information stealthily, he turns himself invisible. In addition upon activating his passive ability to detect undead, he senses an undead reaction causing him to hide momentarily before deciding to seek the target. He notices that the ruins are not made of reinforced concrete and believes he is somewhere in YGGDRASIL, but determines it to not be the case as some of his spells behave differently as those in the game.
Using 'Distant Vision' he sees it to be a mere zombie putting his mind at ease. He later detects another undead reaction, this time heading away from him. Determined not to lose another source of information, Momonga tracks his newfound target. After catching up to the target, he realizes it to be a little girl. He politely greets her and introduces himself as Suzuki Satoru. He asks where her parents are, she states they are gone, indicating she is an orphan. She introduces herself as Keeno Fasris Inberun.