I picked this up because the idea of a former delinquent(kinda) turning his life around and wanting to help other youths really appeals to me. I didn't realise however, that this manga is actually a continuation of several manga series that started nearly THIRTY years ago. Unfortunately, it doesn't look like any of the series has an official translation; fortunately, they're all on this site! So, if you want to get some (read: a LOT) of background info on Mr. Zetton's life when he himself was a high school student, read those manga. (Start with "Crows".)
Be warned though, "Crows", "Worst", their sequels and side stories deal mainly with gang politics and school rivalries, so there are a lot - and I mean A LOT - of characters. I'm talking a few dozen per series, at least. You could do what I did and just skim through most of it (seriously, I'm only just interested in Zetton), but you do run the risk of losing out on some of the finer details of what made Zetton the person he is in this series. Also be aware, he's actually not the main protagonist in any of those series, although he does show up in pretty much all of them.
Anyways, back to this series. It's a well-worn plot trope in that you have a class of troubled students (all boys in this manga) who nobody believes in except the teacher, so it will be interesting to see what spins and twists the author will put on it, if any. Art's pretty decent (not sure what the deal with all the baggy clothes though- does gangster fashion ever change?). While we've been introduced to a large handful of chars (again), the focus has only been on about 4 or 5 of them so far. NGL, I'm not fond of the nurse, only because she (as the only female char in the series so far) feels like a forced love interest. Hopefully we'll see some other potential partners introduced down the road. I also really look forward to some of the conflicts a story like this can introduce (such as a meeting between Zetton and a certain student's father).
Many thanks to Banchou for picking this up and I hope they will continue with the translation!