Well, maybe he is? After all, she did say that between him being either indifferent or obsess over things; she would prefer him to be obsessed with her and also said that she would take in any obsession he expresses for her.MC guessed the 9th Prince absence on the swordsmanship tournament was ML's deed. Which means, he went for obesssion rather than indifference. (╭ರ_⊙)He was interested in her and she say things that proved that she understood him. There is also the fact that things come too easily for him since he is a genius(he's bored).So, there is no reason for him to reject on her offer of taking in everything he does for his obsession towards her. ╮( ̄▽ ̄)╭
Hoho The 13th Prince is doing another action for his obsession