Yagiri Pharmaceuticals, Upper Management is the sixth chapter of the first Durarara!! light novel.
Yagiri Pharmaceuticals has had a drop in their stock, and a conglomerate named Nebula approaches the company with a merger offer. Company head Namie Yagiri is against this offer, as it means Nebula would gain possession of the Dullahan's head they have - an object of the lab's study as well as the object of her brother Seiji's affection.
"Her little Seiji was looking to her for help. He needed her. When she realized how much happier this made her than anything else in the world, she came to a firm decision. She would protect her brother. Using any means necessary."