Elsa and Meili, Assassin Sisters' Dark Diary

Elsa and Meili, Assassin Sisters' Dark Diary (エルザとメィリィ、裏稼業姉妹暗躍日報) is a Gamers shop exclusive limited edition short story that came with Volume 12. This was later adapted and included in the Re:Zero Ootsuka Shinichirou Art Works Re:BOX 2nd.

Summary
When Meili was in her early teens, Elsa received a job to secure the insignia of a young woman named Emilia in the capital city of the Kingdom of Lugunica. Meili accompanied her to the capital, and the pair booked a room in an inn where they kept their belongings. However, the job went awry and Elsa was forced to flee to a safehouse without her prize. As soldiers scoured the capital looking for the Bowel Hunter, Meili entered the dingy safehouse and found Elsa asleep on a pile of hay with wounds coating her body.

Meili complained to her older partner about her tendency to end up in dangerous situations fill of filthy environments. The younger assassin, as she tended to the newly-awakened Elsa's wounds, expressed dissatisfaction that they likely wouldn't be able to use their safehouse again due to the stench of blood Elsa had dragged in. Meili was perplexed by Elsa's wounds, as the Bowel Hunter's power was supposed to accelerate the speed of her recovery. Elsa explained that it was likely due to the opponent she faced—the Sword Saint, Reinhard van Astrea.

Reinhard was the greatest warrior of Lugunica who was widely considered to be the most powerful entity in the world. Nevertheless, Meili was surprised he had defeated Elsa, whom she presumed could only be beaten by Mother. Granhiert reminded Meili that it wasn't her first loss, as she'd also been defeated by Cecilus Segmunt several years ago. Having finished her treatment, Meili and Elsa decided to leave the capital. After procuring a change of clothes for Elsa, Meili used the powers of a Demon Beasts to temporarily change their hair colours.

They soon came across a guard who failed to recognise them and helpfully escorted them back to the main road. Although they initially planned to lay low, the pair discovered a new set of orders awaiting them among their baggage back at the inn. The letter, addressed solely to Meili (much to Elsa's disappointment), instructed her to stoke mayhem in the area surrounding the mansion of Margrave Roswaal L Mathers. Although Granhiert was upset, she decided she would make a doll of Reinhard for Portroute to pass the time. "I'll be somewhat hesitant about lining up with the other dolls." said Meili. When she did, Elsa saw that and tilted her head toward Meili. "Shall I come with you? I'm your surrogate older sister, after all." "No thanks. I couldn’t take it if I ended up being treated like a little sister by this slob of a big sister." "Oh my, that’s not cute at all."; At Meili’s impertinent reply, Elsa too smiled meaningfully as she responded.

The unproductive conversation between the two continued until they went their separate ways outside the capital. The only witness to the dangerous sisters’ whole story was the moon, floating in the night sky.

Characters

 * Elsa Granhiert
 * Meili Portroute
 * Emilia (mentioned)
 * Reinhard van Astrea (mentioned)
 * Roswaal L Mathers (mentioned)
 * Cecilus Segmunt (mentioned)
 * Mother (mentioned)