
MAJOR SPOILER
I JUST READ THE NOVEL AND I REACHED THE REASON WHY THE GUIDE SAID "I OWE YOU"
Basically, the guides are the reason for the misunderstanding in the confession. When MC confessed his feeling to the grand duke, the guides mistranslated (? Mistransmission??) the Grad dukes response.
It wasn't [I despise you] or [I hate you]
HE ACTUALLY SAID
[I LIKE YOU] AAAAHHHHHHHHHH

I love the story so much but I'm still confused about the setting(?)
1. Does the characters (vassals and grad dukes) know they are in the game?
2. If no, does reviving/dying/respawning normal for them?
3. If yes, then... HUH???

1) It does seems they know they're in a game because kings get assigned to them and there are particular rules they follow that come from the system.
2) They are familiar with respawning and dying. The previous 41 Celestial Kings were apparently killed by the Duke for not being good enough. Each king seemed to have 6 lives (I'm not sure if that's true for all players in general) which means the Duke killed each one multiple times to fully get rid of them. The current King (MC) has also been killed by him at least once.
3) Huh indeed. The setting is weird and the author doesn't explain it well.
Being worried that its ai, saying that you’ll be dropping it yet here you are reading in an illegal website
HAHAHHAHAHAHA LMAO
Fr fr