There's usually one unusual one.

In the blended Kerry-Heinz family, it's John Heinz IV. He's the iconoclast. He's the Buddhist educator and medieval armor craftsman and the keep-to-himself individualist. He is the eldest stepson of John Kerry, the Democratic presidential nominee, and he is the eldest son of Kerry's wife, Teresa Heinz, heiress to the H.J. Heinz ketchup megafortune.

Heinz IV is the quiet one. He makes Judy Dean seem like Janet Jackson. The people around him protect him from curious reporters. He wants nothing to do with this campaign, they say. Greta Garbo-like, he just wants to be left alone.

His lust for privacy is noteworthy at the moment because the other children and stepchildren of national politicians have become omnipresently public -- the Bush twins, the Kerry kids, the other Heinz brothers, for instance.

And because he was born into a political family and has joined still another one.

He is the one you did not see at the Democratic National Convention or on "Larry King Live." He is the one who doesn't want his picture in the newspaper, who won't do interviews, who is fiercely independent and even more fiercely private. A rare photo in a recent People magazine shows a smiling man with dark hair and a well-kept goatee.

He does occasionally return phone calls and e-mails. "This is John Heinz," he says in a crackling voice on the telephone answering machine. "I'm not interested in doing any interviews. So . . . sorry to waste your time. But don't bother. Thank you."

We could fill volumes with what we don't know about Heinz IV. With information available on the Internet and some words with the very few folks who will talk about Heinz, the puzzle pieces of his life begin to fit together.

Henry John Heinz IV was born in November 1966 to John and Teresa Heinz. His two younger brothers are Andre and Christopher. Plenty has been written about them.

His multimillionaire Republican father, Henry John Heinz III, was elected by Pennsylvanians to the House in 1971 and to the Senate in 1976. Heinz III served there until he died in a plane crash in 1991.

Newsday reports that at the funeral of his father, Heinz IV read from the works of Trappist monk Thomas Merton. He also quoted "a wise old friend" who said, "A flower cannot proclaim its beauty until it dies."

Heinz IV grew up in Washington and spent summers at Rosemont, the family estate in Fox Chapel, near Pittsburgh. He graduated from Boston College. While there, he became fascinated with Shim Gum Do, a Korean spiritual way that speaks of the mind's sword.

The South Korean newspaper Chosun Ilbo says Heinz IV is a major mover in the World Shim Gum Do Association. The woman who answers the phone at the Boston-based association says she knows Heinz but she does not want to talk about whether he has trained there. And she says she will not answer any questions about Heinz or Shim Gum Do.

After graduating from Boston College in 1989, Heinz studied blacksmithing in Colonial Williamsburg. The Colonial Williamsburg Foundation employs several blacksmiths and Heinz IV served as an apprentice there for a year. In the mid-1990s he lived in Nantucket; in 1996 he moved to a 130-acre piece of land in Bucks County, Pa. He is married and has a daughter.

Combining his affinities for martial arts and education, Heinz IV is founder and headmaster of Tinicum Art and Science School in Ottsville, Pa., which bills itself as America's First Buddhist Alternative School. The dark green school sits long and low on the side of a small yellow meadow. It has a red roof and a half-dozen tall windows.

According to its Web site, www.tinicumartandscience.org, the school "began as an idea for a small, residential, martial arts based program in rural Bucks County and has evolved into a small, intensive high school with a classic liberal arts curriculum."

The students often come from difficult environments, the Web site says. Many of them "have faced a lot of adversity -- chaotic home life, drug and alcohol problems, and chronic failure in school."

The Tinicum Art and Science teachers are an eclectic lot. One math teacher speaks German and Japanese and holds a black belt in a form of Shim Gum Do. Another was a counselor to mentally impaired people in Pennsylvania group homes. And another is a former museum director and plays percussion in a jazz band. No one from the school would speak about Heinz IV.

When he's not at the school, Heinz IV uses his knowledge of blacksmithery to fashion exotic objects in the tradition of ancient craftsmen. He has a Web site, www.herugrim.com, that displays pictures of his metallic handiwork -- a handsome sword, a Hieronymous Bosch-like helmet and other pieces. Herugrim, the site explains, is Old English for "fierce in war."

On the site he writes that he mostly focuses on medieval helmets, cutting tools (such as swords, knives, axes and chisels), hinges, locks and nails. "In regards to the processes," he writes, "I strive to use the same techniques and materials as early tradesmen did. Therefore I primarily use pure iron and simple medium or high carbon steels for most work."

He is also interested in Native American reenactments. Pennsylvania artist Robert Griffing was so impressed by Heinz IV at a restaging of the pre-Revolutionary War Battle of Bushy Run between Native Americans and the English, he took photographs of Heinz and used them to paint "Too Quiet," a realistic portrait of a pensive warrior with a painted face and impressive abs.

"He had a good look," says Griffing, who has been painting scenes from the French and Indian War since the late 1980s. "He was probably one of the better ones out there."

The painting hangs in the offices of the Heinz Endowments in Pittsburgh.

Heinz IV serves on the endowments' board, which oversees $1.3 billion. His mother is the chairwoman. She did not return a phone call.

The president of the endowments, Maxwell King, says, "I know John Heinz a little." King describes him as "modest, quiet, very, very thoughtful."

The foundation must constantly battle against cultural elitism, King says. Heinz IV is a swift, sure voice for working people. He believes in "an equitable society," King says. "He has a really sharp, analytical mind."

In the past few years -- as he has helped raise his young daughter and tried to get his school off the ground -- Heinz IV has been less active in the foundation, King says.

Like his father and other forebears, family observers say, Heinz IV is trying to use his wealth to make the world a better, more intriguing place. In 2000, according to Federal Election Commission records, Heinz IV contributed $1,000 to Ralph Nader. He listed his occupation as "blacksmith," Newsday reports.

So far he has not campaigned for his stepfather, nor does he give any indication that he ever will. He keeps his own counsel. He has separated from the pack. He is not cashing in on his family's phenomenal fame. Apparently he has forged his own life -- of the mind and the sword. And he stays busy.

"Often I make things that strike my fancy," he writes on his Web site. "So I usually have a helmet or knife or two that needs a home."

John Heinz IV, far left, eldest son of Teresa Heinz Kerry, has a quiet life as a Buddhist educator. His more politically active brothers, Chris, left, and Andre Heinz, joined their mother at the Democratic National Convention in July.Artist Robert Griffing used a photograph of Heinz as the basis for his painting "Too Quiet," right.