The world learned of Kim Jong Il's death on Monday, two days after the North Korean leader died of a heart attack. His death immediately placed his son, Kim Jong Un, into the spotlight, as he went from being a Respected General in North Korea to a Great Successor.

The Associated Press reported that within hours of the news of Kim Jong Il's death, state media told the nation that they should gather around Kim Jong Un and faithfully revere the next leader.

But not much is known about the young Kim Jong Un. In fact, it is even unclear exactly how old the young leader is. What is known, however, is that if Kim Jong Un is promoted to run North Korea, he must be ready to continue tough nuclear negotiations with the United States and handle a nation that is reportedly having chronic food shortages.

While Kim Jong Il had a reported 20 years of grooming to run North Korea, Kim Jong Un reportedly didn't have that luxury.

Here are 10 things to know about Kim Jong Un as reported by The AP.

1. He is in his 20s.

2. He is one of Kim Jong Il's three known sons.

3. Kim Jong Un was introduced as a successor in September 2010.

4. If Kim Jong Un take the leadership of North Korea, he will be a third-generation leader. The family has ruled the country of 24 million since 1948.

5. His succession process quickly began a little more than a year ago. The AP reported that Kim Jong Il had 20 years of grooming before his father, Kim Il Sung, founder of North Korea, died in 1994.

6. Kim Jong Un has showed up with his father at state events and reportedly ran the country in the past when Kim Jong Il traveled to Russia and China, according to The AP.

7. North Korea credits Kim Jong Un with organizing a deadly artillery attack on a front-line South Korean island LAST November. That attack nearly started a war between the enemy countries.

8. Kim Jong Un reportedly graduated from Kim Il Sung Military University and speaks several foreign languages, including English. He also reportedly studied in Switzerland for a few year as a teen.

9. He is good at computing and technology.

10. He celebrates his birthday in January. However, the year is unknown and so is the name of his mother.