This is from a Manga, and I don't quite understand how the soredake in the 2nd bubble fits into it? But maybe I am completely off with the meaning of the sentences as a whole - so I've put what I think they mean in italics as well.
I'd say I am a reserved (quiet/solemn) person, but
I also watched Kou
Does the soredake simply add an "only"? i.e. I also only watched Kou.
Any pointers are much appreciated. Thank you!