1) I think it is because Ilya didn't realize that Kaveri was the emperor's concubine. I think he first thought that he was Khaol's normal lover, but then became shocked when he found out that his master was making love with a person belonging to the emperor. It could also be due to the time or place. He just might not have been expecting to see them making love and shouted out in reflex, and unfortunately a guard heard his shout.
2) Heil can't read the minds of the Clandors because he becomes friends/ develops feelings for them. At the time when River first came to the underworld, Heil did not have any feelings for him (either platonic or romantic), so he was able to read his mind. The moment he developed feelings for him, Heil could no longer hear his mind. It's just like when Heil met Forrest. He could also read her mind (that's how he heard all the slander about him). He will be able to read her mind until they become friends and he feels emotionally attached to her (develop platonic feelings of love).
I've got more questions but this'll have to do for now.
1) Ilya's reaction was one that's genuinely horrified though. And for Khaol, for someone who's being secretive about sleeping with the kings concubine the first time Ilya saw them, he was acting quite normal?
2) I think it's the other way around, isn't it? In the chapter, Heil said he became friends with the Clandors BECAUSE he can't read their minds (and a sucker for their tragic back stories). So it doesn't make sense to me later on why he suddenly can read Rivers thoughts, perhaps author forgot about that plot detail?
1) Ilya is a foreigner, so it takes him a while to understand their language and their culture. That's why he probably didn't understand about the whole concubine of an emperor thing. It was only after he understood their culture that he really knew what Khaol was doing. And I think that's also why Khaol wasn't worried at first. Plus Khaol didn't want to wake up his precious lover who was sleeping.
2) Heil isn't really honest with his feelings. He pretends to be aloof and uncaring, but is actual a really caring person. He just doesn't like to admit his feelings for the Clandor clan. He loses his ability when he starts to care. http://www.mangago.zone/read-manga/the_god_of_pain_s_groom/uu/iur_chapter-36/pg-1/
http://www.mangago.zone/read-manga/the_god_of_pain_s_groom/uu/iur_chapter-45/pg-35/
3) Sorry, didn't see this point until now. Nana said that her father thought she wasn't good enough because of her eye, but not that she also thought that way. Khaol never came at all to choose a bride, so she was wondering if there was something that was wrong with the family/ her.
1) Can someone explain why Ilya Clandor here: http://www.mangago.zone/read-manga/the_god_of_pain_s_groom/uu/ibx_chapter-24/pg-1/
Didn't react in horror when he saw Khaol and Kaveri together, but later on, he did?
http://www.mangago.zone/read-manga/the_god_of_pain_s_groom/uu/iur_chapter-30/pg-1/
It wasn't his first time seeing them in bed together, so why did he act as if he did, and caused Khaol to curse his bloodline?
2) Why did Heil say that he can't read the minds of the Clandor bloodline here http://www.mangago.zone/read-manga/the_god_of_pain_s_groom/uu/ibx_chapter-27/pg-1/
And yet here, he can read Rivers thoughts? http://www.mangago.zone/read-manga/the_god_of_pain_s_groom/uu/iur_chapter-33.1/pg-1/
3) Nana says she wasn't chosen as a bride because of her blind eye. http://www.mangago.zone/read-manga/the_god_of_pain_s_groom/uu/tr_chapter-2/pg-1/
So sixty chapters later, why did she suddenly say she didn't know the reason of why she was rejected as a bride? http://www.mangago.zone/read-manga/the_god_of_pain_s_groom/uu/ibx_chapter-67/pg-1/