This strange object is not an incredibly powerful seal as they thought. It didn't stop the Origin god from killing himself so he was able to commit suicide by explosion. But not all of his existence was destroyed. That is why he exclaimed just before he died.
He noticed that his energy refused to enter his arm which was covered by the strange object. So it remained intact after his explosive death. That arm was thrown around because of the explosion.
Fiar, a god of knowledge, saw this and couldn't help but exclaim, "Oh no."
Now technically, the origin god isn't dead yet. After all, his arm is still intact. He began to regenerate from that arm. An origin god can regenerate from a tiny drop of blood much less a whole arm. Unfortunately, the strange object was covering up the parts that regenerated as soon as they regenerated. It is what Fiar saw that made him realize that they might be in bigger trouble than they expected.
