The third son of North Korea’s “Dear Leader” Kim Jong-il appears well on his way to succeeding his father, in name if not in style and substance. He will lead the committee in charge of the funeral on Dec. 28 and will then be referred to as “successor.” Just when he will assume the real titles held by his father is a matter of intense speculation. Past precedent suggests a wait of as long as three years, according to Korean custom. For now, Kim Jong-un, 28 or 29 years old, faces the prospect of manipulation by high-ranking relatives and generals. “He’s very much an untested quantity,” says Shim Jae-hoon, a political analyst in Seoul. His lone qualification, according to Mr. Shim, is that “he symbolizes the house of Kim” – a reference to his grandfather, long-ruling “Great Leader” Kim Il-sung, who died in 1994, and his father.