Dr. William Rutherford is the series' side character. As one of Laguna Glock's colleagues in the past, after Laguna's demise, Biscoe re-hires him and a few other Laguna's assistants. Having knowledge about necrolyzation project, William is chosen to be Brandon's caretaker.
Dr. William is generally a nice guy, but can come across as insensitive when making a point. He initially insists that an undead like Brandon can't feel and delivers his speech in a manner that irritates Mika instead of educating her.
As a doctor, William is a stickler to his profession's oath. Despite having little to no authority in Millennion, he struggles to protect Brandon from further disability caused by Biscoe's and Norton's cruelty. Also, he refuses to commit euthanasia no matter what, true to his loyalty to his profession's oath. In Worth, when Brandon begs William to kill him peacefully so that Brandon won't burden Millennion and Mika anymore, William disagrees and tells Brandon that he goes by the principle primum non nocere, which means first, do no harm in bioethics.
Brandon Heat Edit
William initially considers Brandon as just a soulless reanimated corpse, but after seeing his capability to love and show emotions, William starts to think that he is more than that. Loyal to his profession's oath, William does his best to preserve Brandon's quality of life as a handicapped necrolyzer by using his knowledge as a doctor. As the series progresses, William acts like a big brother figure to Brandon.
Mika Asagi Edit
Because of his bluntness, William first makes a bad impression to Mika. However, William actually cares for her. In A Loan Shark's Tale, when car hits Dr. Tokioka's trailer so hard that Mika is trapped inside the trailer without lights, he takes care of Mika until Brandon returns from his work.
William respects Biscoe due to Biscoe's authority as a mob boss and does everything he wants, although William doesn't always agree with Biscoe. However, William won't hesitate to yell at Biscoe when the situation calls for it.
William respects Norton, but because of Norton's strictness and lack of empathy, William quarrels with him more often than not.
- William is not an original character by Legendary Biologist. As noted in the author's notes, Legendary Biologist is referring to a scientist who talks to Biscoe about anti-necrolyze bullets.
- Brandon's deceased caretaker, Doctor Tokioka, is voiced by William Frederick Knight. And now, the one who replaces the deceased doctor is Dr. William Rutherford.