For those who doubt Sayan’s feelings for Illic like Illic does:

In the novel Sayan’s feelings for Illic was a recurring thing—he was prepared to end his life lest his illness got the better of him leading him to seriously harming Illic, he even made Leisa promise to kill him if he ever attempted to seriously harm Illic. Before he died Sayan even tried giving Illic nearly the whole kingdom in his will, but his advisors and Leisa said that it was too far so he settled on giving him a huge manor and a bunch of riches. Sayan also expressed in the novel that he only ever lived for Illic because he was scared that if he died Illic would be left alone in this world. Sayan also tortured and killed Beize mainly because Beize intentionally tried to harm Illic(he even said that he would not bring Beize’s body to the family because harming Illic was just as equal as harming Sayan and committing treason). Ever since Illic reciprocated his kiss(during the battle in the forest), and actually showed interest in having sex with Sayan (side15) it has plagued Sayan’s mind ever since because Illic is usually cold to him, so he sometimes feels regret for how the relationship started and how it is continuing and he sometimes wishes that Illic would love him back. And there’s just many more reasons as to why Sayan genuinely loves Illic even though he lets the sadistic part of himself win sometimes when it comes to Illic, but regardless he still loves Illic in his own sick and twisted way. I think I should also mention that in the novel he delves deeper when describing his illness and from what I have gathered he is a sadist(obviously), and has multiple personalities, only two actually(one is what he considers to be his true self: treats illic as one would treat their loved one, sympathetic. The other one is the one we see when torturing Illic and other victims, the sadistic prick cares about pleasure, and sociopathic). Many times in the novel he argues with himself and what I mean is that those two personalities argue with each other—as for Illic, he has a bit of Stockholm syndrome, but he genuinely does care for sayan(I wouldn’t say love though that’s a bit of a stretch). Also keep in mind that most of these examples from the novel are In Sayan’s perspective and most of this manwha is in Illic’s perspective. Illic views himself as an undesired individual leading him to think that Sayan would actually never want him. So when readers read the manwha only, they are mostly seeing Illic’s perspective which is filled with doubt about Sayan’s feelings or anyone’s feelings for Illic. In the novel he expressed a lot of insecurities about being a rugged mercenary.