Is Undertaker in all reality evil?

I dont want to believe it! Hes my kegemaran character and up until know ive only read halfway through Volume 9 but i read in the Kuroshitsuji Wikia and his synopsis in the Ship Voyage Arc. Apparently he is the own who created the zombies? And he tried to kill Grell and Sebastian? But i just cant believe it! I mean hes Undertaker, i Cinta him being the quirky weirdo we all know and love! Is he really bad? atau maybe the way they wrote it they meant it to be a bad portrayal? Is there any way that Yana could turn the story so that hes not actually bad but hes good. If she doesnt do anda think that Undertaker would still be part of the Manga? I mean Grell killed Ciel's aunt and hes still a part of that Manga, he was even a main character(ish) in Kuroshitsuji season 2. And Lau well anda know what he did in the Anime and he was still in Kuroshitsuji 2.
So basically im asking to those who have read Chapter 50-60 if he is indeed evil and if its THAT evil that itd be weird for me to be him for Halloween?