Jae-San is a huge man, with his physique easily exceeding that of a normal human being. His hands are large enough to break a table with a slight push of his hand. He has an elderly appearance with white hair and wears glasses.
Jae-San is proud of his grandson, Jun Ju-Gok and cares for him. He also has a size complex and doesn't like it when people comment on it. He believes that people need to be born with strength and cannot become strong with sheer hardwork. When Ju-Gok lost to Il-Pyo, he asked Il-Pyo to become his student without any regard for his own grandson. Inspite of all of that, he is shown to be proud of his grandson.
Jeon Jae-San is fist seen sitting on at a table in a meeting of the Six Sung, where he receives a message of the Six being. He is then seen encouraging his grandson Jun Ju-Gok, who is participating in the God of High School Tournament.
Jae-San later arrives to the stadium of the GOH Tournament, to watch his grandsons match against Taek Jae-Kal, alongside a fellow member of the Six and the organizer of the tournament, Park Mu-Bong. He is then enraged by Jae-Kal humiliating his grandson.
Later Jeon Jae-San is seen mourning his grandson, who was taken over by Greed and killed by Taek Jae-Kal. He tells Park Mu-Bong, that he has lost the Six Sung Company, due to the stockholders siding with the JG Group, which is owned by Taek Jae-Kal's family. He then demands to be able to see Jae-Kal, but Mu-Bong denies this. Jae-San then attempts to attack Mu-Bong, but is stopped by Seo Han-Ryang, another member of the Six. Jae-San then questions Mu-Bong, why he is even continuing with the tournament, now that he has found the Key, Park Il-Pyo, to which Mu-Bong responds that they need more strong fighters to fight against their enemies.Mu-Bong then promises, persuaded by Han-Ryang, that he will give Taek Jae-Kal to Jeon Jae-San after the tournament ends.
He later appears at the stadium, helping Mu-Bong and the Judges, in the fight against the Bishop Sang Man-Duk. Jae-San teleports all residents of Seoul outside off the city borders, and uses the missiles launched by the U.S.A. to make a giant bomb which he launches with a giant meteor, and also trap inside a barrier surrounding him and Man-Duk, to kill both of them. This fails, because Jae-San needs to disable the barrier, to protect the people fighting below the stadium. Because of the explosion Sang Man-Duk is greatly weakened and Jae-San is killed by it. Before he's death Jae-San sees Taek Jae-Kal absorb the Key and later being defeated by the Monkey King Jin Mo-Ri. His last thoughts are about his grandson and how proud he is of him.
World Tournament Arc
Jeon Jae-San appears to Seo Han-Ryang, right before the latter's death.
As a member of The Six, it can be assumed that Jae-San has a high level of skills. He can also use Charyeok and specializes in wizardry. His skill is so great that at the age of 37 he became a grand mage and at the age of 47 he became a member of the six along with becoming the great magician of the world.
Alchemy: This allows him to create/convert objects from pre-existing materials such as he turned 567 nuclear missiles into a massive nuclear missile. It also imbues the object with magical power.
The Great Magician: It appearance has not been seen but it was said that it is the strongest magic using charyeok in the world.
Anti-Teleport: As the name suggest this prevents teleportation abilities to work locking the opponent in the confined space.
Teleport: As the name suggest this allows for teleportation from one place to another. He is so great with this he can teleport an entire province of people miles away.
Meteor: As the name suggest this allows him to summon a massive meteor from space accompanied by smaller meteors. when this is combined with alchemy it was powerful enough to severely damage a nephilim summoned by King of the Earth, a feat considering at the time his taboo hasn't been lifted.
Jeon Jae-San share his title with his charyeok's name.