I'm guessing that whatever the original Hero party fought killed them all and possessed their Divine weapons, which are parts of their soul. The previous blacksmith made the Blue Stones to seal the evil and keep it from jumping from weapon to weapon, which prevented the evil from spreading.Was the spear turning into an eyeball monster a part of the sealing spell, meant to absorb the rest of her life? Or maybe the spell Yumine knew was a flawed version. Or was it something Aria did? Nevertheless, the sealing spell obviously wasn't good enough, so Yumine would have died for nothing.
I'm actually more interested in seeing how Phila and Relius's relationship will be after this. Especially if she learns stopping Relious would have been totally meaningless.
It looks like the spell failed because whatever is possessing the old Hero's body tried to hijack her spear.So... Call me crazy, but a mystic weapon that suck out your life in order to do a spell, wants more life than you got so the spell fails, turns pitch black, and sprouts a bazillion eyes... Are we sure these are sacred?I
Everything we knew about blacksmiths was wrong, so I'm increasingly iffy on these sacred weapons.