I don't understand what the Yakuza is?

Question:

I just read they are helping the victims of earthquake.
Don't get me wrong, I think that is great, but won't the government be arresting them or taking some action against them?
Are they even bad?

Answer:

in old days, Yakuza's roles was resolve "cannot resolve in law" problems.
and save poor people.
those Yakuza's spirit called " 仁義" (JINGI)
but they ware evil / criminals for bakufu (government)

nowadays, Yakuza is almost Zainichi Korean.
they are just mafia.
but minority traditional true Japanese yakuzas still had Jingi.
I believe so.