Her name comes from (ヤクいさん) "Medicine" and "Calamity" is the drug addicted and most popular Nijiura Maid. • 2005/10/11.
• [appeareance]
Yakui-san is short because of her drug abuse. She has a purple bob-cut and maid outfit (sometimes the outfit is blue) with purple and white striped stockings. She is often pictured drooling or vomiting with a crazed look in her eyes. Once a month, she is tied up and de-medicated to make her more mature. The handcuffs on her arms are a remnant of that time and she is not a criminal (it is rare that she prescribes and takes illegal drugs and is not a criminal, but this thread is treated as such)
• [source material]
She was kicked out of her parents' house because she was messing with the products of her family's drugstore. Her knowledge of medicines is top-notch, ranging from happy powder to drugs undergoing clinical trials. She has access to both legitimate and illegitimate drugs, and is also able to prepare her own original preparations.
When off her drugs, she's rather sensible, and when she's on her game, she's funky and capable, but if she overdoses even a little, she's peaky and useless. When she's on her game, Yakui-san can see things she can't see and hear things she can't hear.
Because of her drug abuse she is a part of the Inappropriate Maids along with Shitai-san and Dorei-san.