Yu Han Sung

Yu Han Sung is a Ranker, the director of tests on the Second Floor, and the first main antagonist in the series.

Appearance and Personality
Yu Han Sung is a fairly normal-looking man with blonde hair. The one odd thing about him is that he looks like a woman. He always wears robes, usually blue and yellow.

He is quite intellingent and perceptive. He is also addicted to coffee. Behind this simple outer shell though, is the fierce and deadly "Submerged Fish" who destroys those who may be dangerous to The Tower.

Plot Summary
Yu Han Sung was one of the Rankers proctoring the tests on the Second Floor. He directly organized the Door Test, in which the Regulars had to rely on a few scant clues to select the "correct" door out of twelve identical doors. The real answer to the test was in fact to open any door before five minutes were up.

Later, Yu observed the hide-and-seek test with Leo-Ro. He is in charge of grading the overall team scoring. He talked to Lero-ro about Koon's performance, and talked cryptically about how Regulars would have to drop off "excess weight", signifying comrades, as they climbed higher and higher up The Tower. He also revealed his cruel personality as he stated that he wanted to destroy Koon due to Koon's multi-faceted personality.

He tracked down Ren and engaged him briefly, before saying that their goals were the same and that there was no reason for them to fight. He then revealed his position as the "Submerged Fish" of the Second Floor.

He announced the results of the Position Tests, and when Mauchi became angry he snapped his bones with Shinsoo. Koon then came down and said that he wished to get a test from the Guardian, to which Yu replied that he was insane, and that to get such a test one would need to be an Irregular. When Baam revealed that he was an Irregular, Yu allowed him to see the Guardian.

Afterwards, Yu told Baam that he had been trying to destroy him all along.