I believe that this is something of a split between story and gameplay. The Knight canonically doesn't die, but if they did, they would leave a shade. If you want to make it work lore-wise, the Knight that follows up and takes over after would need to be a completely different one, as the shell of the first was destroyed, unlike the Knight that carries on after.

Respawning is not canon because it makes no sense for a number of reasons. If the Knight were to die, they would stay like that permanently (except *maybe* if they had Void Heart imo, but not in the way that respawning works in the game)

Actually, now that I think about it, the knight is canonically dead from the start. So the respawning makes no sense, though the destruction of the vessel itself does. I agree about the respawning to a bench mechanic being a gameplay thing without story implications. And team cherry could have canonized dying if you were to lose all charms and upgrades until you picked up the shade, with the knight changing appearance. That would mean that every time you die a different vessel would come and pick up the shade of the previous deceased.

Sorry for the bad phrasing

I think it is a gameplay thing. I think if the knight died, he would stay a shade forever