Ragnarok
Ragnarok is a manga series.
In detail
It is associated with South Korea.
Sources
Each source is named with the standing the house places on it, so the evidence can be weighed rather than taken on trust.
reference work · Reputable secondary · Wikipedia
“Ragnarok (manhwa)”, English Wikipedia, consulted as further reading
Consult the sourcereference work · Reputable secondary · Wikidata
Wikidata, structured authority record Q583094: Ragnarok
Consult the source