Is this world the first one with high level characters?

[ijuinkun]

The possibly-novel thing about Goblinoids is that they were created with the intent, from the start, that their entire purpose for being was to supply combat experience for whoever defeated them. They were, for all intents and purposes, meant to be sapient prey so that the races whom the gods actually cared for could hunt "The Most Dangerous Game".

"High level" may have existed previously in the sense of "mortals powerful enough to become demigods or to challenge demigods", but it is only because the current world is a "self-aware fantasy parody" that levels and stats and such have explicit numerical values.