I am a Galerian. A life-form created by Mother, the new God of Earth. We Galerians are to inherit the Earth after she destroys all of the humans. The reason for the necessity to kill them should not need to be explained.
And my brother- Rion: I want to kill him for two reasons. One, he carries the Virus Program that can kill Mother. Two, he was given the special mission, the one that I wanted, to retrieve the girl with the Launch Program in her head. So, because I want to and I have to.
[considers Karkat's dumb little problem]
Maybe you should create a database for that information if it is both complex and frequently needed to explain yourself.