pisses me off actually. The author clearly doesn't like the "happily ever after" trope, especially with how he showed the first band of dragon hunters dying at the hands of kamui. This is later cemented in the death (?) of Starlia. There is seldom a happy ending, or even a truly bittersweet ending that is not really interrupted for the protagonist and his companions.
Thus, having these two have this ending doesn't sit well with me.
TLDR; Should've made their deaths painful and despairing, just as they are for everyone else they've killed.