Eunhyuk actually comes from the royal family, no joke.
I was so bored that I did some research on Super Junior members’ family clans, and came up with some surprising results. Who knew that Eunhyuk, and Heechul too, were actually descendants of old kings?

HRH Prince Eunhyuk
Before we go on, understand that only the noblepeople(yangban) could have last names in Korea before Japanese colonization. When Japan colonized Korea, they gave last names to peasants and slaves, and let them choose whichever last name they desired. Most people who belonged to the lower class chose Kim, Lee, or Park as their last names and faked family trees so that they could pass as noblepeople. A lot of slaves chose the last name of their noble masters. 70~90% of Koreans who claim that they have noble blood in them actually don’t.
Anyways, I’m making a dangerous assumption here that all Super Junior members’ ancestors were real nobles. Most SJ members except Hangeng apparently come from famous noble family clans.
How to read the name of a family clan:
Andong(the bon-gwan of the family clan) Kim(the last name)
This tells us that just because Ryeowook and Heechul are both Kims, that doesn’t mean that they are related.

Leeteuk(Park Jungsoo)- Miryang Park
Ah, the second biggest family clan in Korea. I mean, don’t ask me how many peasants and slaves faked their genealogy back then when Japan colonized Korea. Anyways, if Leeteuk really is a part of this clan, he’s a great-great-great-greatx43850 grandson of Hyeogeose of Silla. So he has a 1/1000000000 drop of royal blood in him; awesome. Micky Yoochun also comes from this family.

part Indian?
Heechul(Kim Heechul), Yesung(Kim Jongwoon), and Kibum(Kim Kibum)- Gimhae Kim
There are so many Gimhae Kims I know, it’s not even funny. Established by King Kim Suro, the first king of Geumgwan Gaya, a part of the Gaya Confederacy(an old kingdom that once existed in the southeastern part of the Korean penninsula), this is the biggest family clan in Korea. Anyways, this proves that the three have some exotic blood in them; in folktale, King Kim Suro married an Indian princess from Ayodhya(don’t ask me how she got there).

His Royal Highness Prince Eunhyuk
Eunhyuk(Lee Hyukjae), Sungmin(Lee Sungmin), and Donghae(Lee Donghae)- Jeonju Lee(the Royal Family!)
Apparently all the Lees of Super Junior come from the last royal family of Korea. Eunhyuk’s the only one that I’m sure that belongs to the Jeonju Lee clan though. He’s the descendant of Prince Hyoryeong, the intelligent, religious older brother of King Sejong(could that explain why Eunhyuk’s smart and rumored to be religious?) As for other members, I’m not so sure. I have a feeling that a lot of people who claim that they’re part of this clan really have no drop of royal blood in them.

Kangin(Kim Youngwoon)- Seongsan Kim
I bet this is one of the smallest Korean clans. There’s literally no information about Kangin’s family clan. If you have any information, leave me a comment with a link or something.

Kyuhyun(Cho Kyuhyun)- Changnyeong Cho
A lot of famous scholars and Korean Nationalists have belonged to this clan. The first Korean family clan ever to use the last name “Cho,” which was actually given to the progenitor of the clan by a king of Silla. Some Changnyeong Chos I know claim that they’re related to Queen Seon Duk(watch the drama ‘cuz it’s awesome!), but the real progenitor of the clan I think is a son-in-law of King Jinpyeong (Queen Seon Duk’s father).

Totally Korean!
Siwon(Choi Siwon)- Jeonju Choi
Not to confuse you, but his family isn’t the same as the Jeonju Lee family. The two families might’ve been established at the same region or something, but they’re NOT the same clan. Anyways, Siwon belongs to one of the oldest family clans in Korea- he should be proud of that.

Shindong(Shin Donghee)- Pyeongsan Shin
Um..well, he’s a descendant of a famous general who helped Emperor Wang Gun establish Goryeo Dynasty. His bon-gwan’s actually at North Korea, wow.
Identifying which family clan you belong to is not as important as it used to be, although individuals still take a lot of pride in his/her clan. It’s the 21st century and all of this stuff is just for fun:)
I have no information on Hangeng currently. If you have any information about his genealogy, let me know.
Written by SJFF
Do not take out!
Learn more about bon-gwan here: http://en.wikipedia.org/wiki/Bon-gwan
All of this stuff can be pretty confusing since you kind of have to know the Korean history to understand this. If you have any questions, then just leave me a comment:)