He’s back because there are always new delinquents that need a lesson from teacher.
Tohru Fujisawa’s career really took off with Shonan Junai Gumi. (Unless Adesugata Junjou Boy was some sort of critically acclaimed masterwork that no one ever talks about in the US.) In Shonan Junai Gumi we find Eikichi Onizuka and Ryuji Danma as two rough and tumble bikers trying to lose their virginity while fighting the worst delinquents in Japan. The series was popular enough that it got spun off into a sequel series, called GTO, where Onizuka becomes a teacher and Danma makes some guest appearances. While Shonan Junai Gumi was popular it never even dreamed of being the smash hit that GTO was. Since GTO ended Tohru Fujisawa has drawn other manga like Rose Hip Rose and Animal Man, just been the writer on manga like Eyaminokami – The Plague Princess and Shonan Seven, and even tried to spin-off other Shonan Junai Gumi characters into stand alone manga like Danma and Saejima Despite all of that in the end it seems like the character he always come back to is Onizuka.
If you remember GTO Shonan 14 Days was a Manga of the Month on the blog all the was back in 2011 but it was technically not a sequel. It is actually a side story that improbably takes place in two of the weeks between the penultimate and final chapter of the original GTO manga. But this time we get the true continuation of Onizuka’s mythos.