"사랑해, 너만을. 변하지 않도록 영원히 널 비춰줄게." I think the sentence is a little unclear with the 도록 part. It could be interpreted as: "so that (I/you/us/our love) never change..". ("you" and "our love" would be the likeliest candidates, I think) The translation you listed took it as "our love" and used "it" for that. It also simplified "so that it won't change" to "it won't change". Stricter translation would be something like "I'll shine on you forever so that our love will never change". So I think it is just a case of a loose translation to make it smoother. About "미치도록": 미치도룍's 도록 falls in your #2) sense - "to the point/extent" or "till". It means "to the extent/point I might get mad", "as if I'm mad". But in most cases "madly" will be good enough. 미치도록 사랑합니다: Love you to madness; Love you madly. 밤늦도록 걸었다: Walked till late into the night. 목숨이 다하도록 싸우다: Fight till the last breath of one's life. * Sometimes it 도록 becomes 토록. 영원토록: till the end of time; forever. 그토록: So much; to that extent.