Im REALLY confused about what happened when the trolls went on a murder spree and half of them died. Could you just explain that part?

Vriska killed Tavros because she didn’t like him and she was also being a bitch. Gamzee killed Nepeta and Equius after he became sober and looked into Lil Cal’s eyes. Eridan dueled with Sollux and knocked him out. Feferi thought Sollux was dead so she went to stab Eridan and he killed her with his White Wand. He then killed Kanaya but she came back as a Rainbow Drinker and sawed him in half.