I read on another forum a thread concerning left and right hands and anything else referring to left and right. Right is masculine, strong, power, action, conscious thought, intellect, and trust, etc. Left is female, weak, passive, intuitive, unconscious or subconscious , emotions, can be suspect(?).
In Christianity, on Judgment day people are sorted according to merit, the saved or "good" going to the right hand of God, the damned or "evil" going to the left.
Myself I prefer to leave out the "good" or "evil" from consideration, and think of it as either masculine or feminine, active or passive, intellect or intuition, thought or emotion, conscious or subconscious and draw insights from that aspect.
So a Knight could represent the masculine influence perhaps, the thinking, conscious part of the element he represents. The idealistic view, rather than the final realization of it.