[Switchblade]

Definitely Philip. Even though it was clearly established that it was coming, the moment itself was absolutely heartbreaking. The reversal in the following episode doesn't do anything to negate the impact of that original scene for me.

Meanwhile, by the time we got to Kengo and Koyomi the death of the non-human supporting character had already become so cliche that I found both incredibly boring (although that's not the only reason why Koyomi's death meant nothing to me, in fairness).

Never really got upset about Otoya's death. We knew very early on in the series that he died and, honestly, after what a douchebag he'd been to Yuri I didn't really care much what happened to him.

Oh, I will give some props to the whale monster from Black, too. Probably the most moving monster death in the entire franchise.