Incarceration is a great punishment by itself, depriving someone of their freedom of movement is already quite a lot. What I meant is there is no need for a vengeful justice beyond that.

If an individual is dangerous for society they shouldn't be in it, this doesn't mean forever if there is a possibility of rehabilitation. There are many monsters locked up that probably should never be released, in that sense the justice systems of Norway, Germany, Sweden and others work well: you are locked up to 20 years, after that your case is reviewed and if you are still deemed a danger to society you get it prolonged, a few times this goes on for life.