Could someone please explain to me why Eridan killed Feferi and Kanaya?

(OOC) Well, he did Cinta Feferi. And he killed her because she was angry at him for KO'ing Sollux. When he knocked Sollux out, Feferi tried to attack him, but he blew a role in her torso with his wand, killing her. The same goes for Kanaya, although she attacked him because he destroyed the Matriorb. The Matriorb is the thing that would have hatched a new Mother Grub. As berkata before, Eridan destroyed it in a "hope-splode", adding up to his God Tier of Prince of Hope (Destroyer of Hope), as he destroyed the only thing that could keep the troll race going. In anger, Kanaya ripped out her chainsaw and leaped for him, but her lipstick chainsaw was no match for Eridan's long distance, power-as-fuck white science wand. So, to recap, Eridan only killed them in self-defense. He did Cinta Feferi, and he was Friends with Kanaya.

Many Homestuck peminat-peminat like to say that Eridan killed Feferi because she went with Sollux. Contrary to popular belief, he killed her because she attempted to kill him for attacking Sollux, and he was therefore defending himself. He proceeded to kill Kanaya when she came at him with her chainsaw when he destroyed the Matriorb, thus destroying hope for the troll race.