The male leads are incredibly cold. Nonchalant, indifferent and embodied by apathy. The cold ambiance is definitely similar between the two dramas. Environments are alike as well. The fantasy element obviously also matches the fantasy in Doom at Your Service. The cinematography is also similar. If you wish to dwell into mysterious fantasy dramas, I would definitely recommend Doom at Your Service. Both plots are heavy, but they have a satisfying ending. The sickness/disease aspect is also present in DAYS. Hope you enjoy:)