Yuyu Hakusho came out in 1990, and its basically got every cliche of the isekai genre in it, while also being one of the biggest shounen series of that decade. So much so that it was one of the earliest Toonami dubs. Shit its probably one of the first to use the literal Truck-kun as its plot device to start everything. And I think "supernatural/ghost world" counts as "another" for the definition of isekai.

For additional info, the very concept of the "harem" genre was invented by a woman, one of the now richest women in Japan who has had ongoing series since the 80s. But they wouldn't know that either.

Yuyu Hakusho came out in 1990, and its basically got every cliche of the isekai genre in it, while also being one of the biggest shounen series of that decade. So much so that it was one of the earliest Toonami dubs. Shit its probably one of the first to use the literal Truck-kun as its plot device to start everything. And I think "supernatural/ghost world" counts as "another" for the definition of isekai.

For additional info, the very concept of the "harem" genre was invented by a woman, one of the now richest women in America who has had ongoing series since the 80s. But they wouldn't know that either.