This is one of these series that's a prime example of why we shouldn't judge a book by its cover.
http://www.reader.japanzai.com/?manga=Oyaji
I guess you gotta be into stuff like Violence Jack and Kongou Banchou to give this series a chance since Oyaji gives off similar vibes in the first couple of chapters. Those who keep reading will come to realize that this guy is more than just a man of a few words with monstrous strength and a violent past.
Despite the so-so quality of the translations and the rough art, which I bet will make some think of Baki, this series manages to deliver some of the most touching scenes I've seen in a seinen manga.