Rasetsumaru: he rips their heart out with his bare hands, then crushes it.
Kusaregedo: he drags his opponent offscreen and then eats them while you hear screaming.
Enja: He dissolves them in a pillar of flame.
Jubei: He quadrasects his opponent.
Suija: He knocks the loser down, then uses his telekinetic powers to lift them to a point above him. Then you see him close his hand into a fist, and hear a scream. As if it wasn't bad enough, he then leans back as blood rains all over him.
Hanzou: Breaking a foe's arms, legs, and ribs before piledriving him skull-first into the pavement.
Kyoushiro: Burning the loser alive.
Basara: Pulling the foe with them into a pit where we see blood and eventually the defeated foe's head fly up from, cackling madly the entire time...