Richard Dragon, Kung-Fu Fighter 18 (Nov/Dec 77) features a cameo by a major villain and the biggest twist of the run. Sadly, the O'Neil and Estrada tale is the final issue, and doesn't even come close to resolving things.
The story picks up from the end of the previous issue. Ben Turner manages to fall once again into the hands of Professor Ojo and Lewis. This is the last we see of those villains in this story, though. Professor Ojo next appears in the pages of Green Lantern the following year.
Richard turns to Barney Ling for help, but Barney has no idea what has happened to Ben, and no idea where to find Ojo or Lewis. Richard Dragon falls into despair at this point. He stops teaching at his dojo, and just gives up on everything.
It's a good thing a second plot thread starts up at this point, or the comic would get very dull indeed. Captain Boomerang makes a cameo, in prison after his defeat in Secret Society of Super-Villains a few months earlier. He sees a vicious fight between two other prisoners, and lets the winner know about an underground martial arts competition coming up.
Lady Shiva comes to visit Richard, and sees what a mess he has become. She bitches him out, and informs him of the same match. Richard decides he needs to follow her advice and get himself back into form if he is ever going to find Ben. That's it for Lady Shiva in this story. She is not seen again for ten years, returning in The Question shortly after Crisis on Infinite Earths.
The underground martial arts fight club is presided over by the Bronze Tiger. Richard winds up pitted against the prisoner we saw earlier, and defeats him. The guy should have been no competition for Richard, but he has let himself go to seed.
Bronze Tiger then challenges Richard, but before the two can fight the police burst in. Since Richard has a reputation for fighting for the good guys, people think he brought the cops, and begin to attack him. The cops consider him just another one of the bad guys there, and are after him as well. To his surprise, Bronze Tiger fights to defend Richard and keep the other away.
This makes sense on the very last page, when the Bronze Tiger's mask comes off, revealing him to be Ben Turner. What has happened to Ben to turn him into the Bronze Tiger? It will take a heck of a long time for that to get explained.
Still, Bronze Tiger does return before Richard Dragon does, showing up in Detective Comics in 1979. Richard Dragon has to wait for a "Whatever Happened to...?" story in DC Comics Presents in 1981.