Did they attempt to find another potent weapon like that? No. But how exactly did they come to know it is? Did they go through all the documents? No. Okay, Siegfried might have been the most effective weapon that existed in that world. (Berseria made a lot of lame plot points in Zestiria better.) Rather than letting live a futile life, they let him die by his creed. We can safely assume there was nothing more that could be done to restore Eizen rather than giving him a mercy kill.

In Zestiria, Zavied has those bullets and still wasn't able to help Eizen.

You say they didn't try to save him but if you notice in the cutscene titled 'Siegfried's Manual,' the characters are discussing a type of bullet imbued with mana that can sever the influence of malevolence. it makes you think how badly executed Zestiria's story was. To think that he'd be killed by idiots who didn't even try to save him. He managed to defeat him, but as a result he ended up being a dragon. Originally posted by lelouiserui:Hundreds years after Berseria, Eizen fought with a lord of calamity.

Download free tales of zestiria eizen