Raph had been stupid to leave the lair alone.
Of course his brothers had followed him, and he'd barely been able to push Mikey away from the fatal attack during a foot ninja ambush.
"Raph!"
"I'm fine, go help Mikey!"
Keeping his back to his brothers, Raph bit into his wrist guard, barley making a sound as he pulled the knife from his chest.
Nobody saw as the rain carried blood down his plastron.
He could feel himself slipping away, but he greeted Death with a soft smile, because with his last breath he saw Mikey struggle to his feet.