??? both were in the manhwa. yes, not as detailed in the novel but not the point of being"irksome" lol
no 1 was in chapter 75, he said "if woo heejae were my successor he wouldnt be this soft. id have taught him to eliminate enemies by any means necessary" and thats enough for readers to catch the nuance. thats just how manhwa adaptations are
no 2 was in ch 79. you know this is mtl-ed right? aka dont take everything at face value. the part where heejae mentioned irok was a little weird so i checked the raw, both novel and manhwa. and guess what
"그, 이록이가 되고 싶다고 하면... 말리지 않겠습니다"
“…이록이가 그, 되고 싶다고 하면 말리지 않겠습니다.”
both version said the same thing
Guess I was expecting it to be explicitly stated in this chapter since I read it a couple of months ago, so I was as feeling like the full reveal would be now since I also remembered MC realizing in this chapter that he basically couldn’t rely on his cover as a disciple when his father explained that it was because he wouldn’t kill that he knew he couldn’t be his disciple. It made me chuckle just him thinking that he had to give that up when he was trying so hard to hold on to that narrative. This chapter remains my favorite so my anticipation to see it in the webtoon was sky high I guess.

Some things are missing or not stated as clearly as in the novel… which is a little irksome considering I read that novel though google translate lol.
1. The reason he felt off about MC telling him some story about being his disciple is because he would’ve taught his disciple to be ruthless and kill his enemy. When MC failed to kill blue haired in the last arc, he immediately knew something wasn’t right. That’s why when MC called him “dad”/“father”, it clicked for him because he would’ve made sure to tell his son not to kill to preserve the good parts of him in that sense. And everything else that felt incongruous about MC’s story and the way MC showed up and stuck around finally clicked for him.
2. At the end of their exchange, after he asked MC to be his son, MC’s condition is that it’s up to Irok aka his Minnie me aka his little brother. So as long as he says yes, then he won’t have anything against it.