When GoseiKnight showed up in Goseiger, he didn’t like humans much. He ended up working with the Goseigers simply because they both happened to be fighting the UMA Beasts. Now that the UMA Beasts are gone, what reason does he have to fight the Matrintis? As a humanoid headder, GoseiKnight has more in common with robots than people anyway.
Well, going into why GoseiKnight changes his mind is what the episode (Goseiger 34) is about, but eventually he does decide that humans are okay and the Matrintis need to be shot in the face. So in this clip you’ll see GoseiKnight teaming up with the Super Goseigers to shoot a revived Zan KT in the face so hard that he explodes.
If you’re wondering how Zan KT got revived– well, that’s the nice thing about robots, you can just rebuild them when they break. More importantly, it means Goseiger can reference… uh, Short Circuit 2.