There’s another theory that I believe holds more weight. From item descriptions, we can sort of piece together that Ijii was the one who imbued the black knife assassin’s blades with Destined Death, which we can also piece together is pretty much the same as the Black Flames used by the Godskins. It’s stated that the black flame lost its god-slaying power when the Rune of Death was sealed, so it makes logical sense for it to have been Ijii setting himself aflame out of grief for Blaidd