good/evil room tl;dr.
"Evil" Light is: judgmental and controlling; self-destructive, bitter and unsatisfied; seeks to connect to people by forcing his personality on them, rather than opening himself up to theirs; egotistical; desperately afraid of contact; mistrusting, intensely secretive and private; angry and vengeful; lonely because of his own arrogance, believing nobody is good enough to reach him or worthy; and yet paradoxically insecure, believing he's not good enough (both tie in to "unsatisfied"; he isn't satisfied with the world, and he isn't satisfied with himself, because neither is what he wants); a perfectionist; empty, constantly trying to take and conquer and possess; vain, highly invested in being the best and looking flawless; has little respect for other people, is the little voice always supplying I could have done that better; toys with and misleads people (sometimes subconsciously) just to prove that he can, which ties into the vanity and the control, because he likes manipulating how people see him; because of the "unsatisfied" bit, is also rather depressed (apathetic and deeply unhappy) - is the part which goes why bother? it's never going to be good enough; an absolutist; hateful (see "unsatisfied"/"insecure"), and motivated (to change/"fix" the world) by that hatred. He is contemptuous of other people, and judges them, and wants to turn them into what he thinks is right, because he hates and judges and is self-righteous; and this is how he tries to fill up his self-identity, and this is his definition of being a good person. He's the part which is motivated to Be A Good Person (do volunteer work, help other people) in order to gain praise, to reassure himself that he's superior to those around him, and in order to satisfy his ego.
"Good" Light is: accepting and peaceful; nurturing, hopeful and grateful; opens himself to people; self-aware and balanced, trying to give and share; creative - he's the artist; enjoys life, enjoys being himself; actually likes other people - likes interacting with them, sees them as something valuable; is also, curiously enough, the confident side - "evil" is egotistical and superior, but "good" is the one who actually believes in himself; humble enough to make room for other people; forgiving; spontaneous; willing to live with imperfection; enjoys the process just as much as the end goal - which means, he's okay with imperfection, because it's working to get better from which he derives pleasure, rather than the constantly-frustrated goal of being the best, and that, coupled with the "hopeful" bit, means that he's the one with a lot of the drive and the vision (although "evil" has need and obsession); honest and genuine; secure enough to trust; believes very strongly in morals and goodness; but, unlike "evil", isn't self-righteous and hateful about it. He is complete in himself, and doesn't have to compare himself to other people/tear other people down for support.
The things the Lights share are, obviously, their intelligence; and anxiety. I've always written bassy as having a lot of anxiety issues as a child which he has mostly outgrown, but still linger, and they're rooted in both his obsession with control ("evil") and caring a lot about the world/other people ("good").
"Good" Light is: accepting and peaceful; nurturing, hopeful and grateful; opens himself to people; self-aware and balanced, trying to give and share; creative - he's the artist; enjoys life, enjoys being himself; actually likes other people - likes interacting with them, sees them as something valuable; is also, curiously enough, the confident side - "evil" is egotistical and superior, but "good" is the one who actually believes in himself; humble enough to make room for other people; forgiving; spontaneous; willing to live with imperfection; enjoys the process just as much as the end goal - which means, he's okay with imperfection, because it's working to get better from which he derives pleasure, rather than the constantly-frustrated goal of being the best, and that, coupled with the "hopeful" bit, means that he's the one with a lot of the drive and the vision (although "evil" has need and obsession); honest and genuine; secure enough to trust; believes very strongly in morals and goodness; but, unlike "evil", isn't self-righteous and hateful about it. He is complete in himself, and doesn't have to compare himself to other people/tear other people down for support.
The things the Lights share are, obviously, their intelligence; and anxiety. I've always written bassy as having a lot of anxiety issues as a child which he has mostly outgrown, but still linger, and they're rooted in both his obsession with control ("evil") and caring a lot about the world/other people ("good").