As two of YouTube's most successful rappers--their "Epic Rap Battles of History" channel has more than 1.2 billion total video views and almost 5.4 million subscribers--Nice Peter and EpicLLOYD (Peter Shukoff and Lloyd Ahlquist to the historical record) met while freestyle rapping. Except it wasn't at some park bench or open mic event; it was during a party at Ahlquist's house in Chicago, where both had moved to pursue improv comedy.

Shukoff, who also performed musical comedy around the city, eventually joined the group Ahlquist had been in since college, Mission Improvable, and both spent several years touring and performing at local theaters such as iO. Eventually they each moved to Los Angeles, where Ahlquist helped run a comedy theater and Shukoff started making YouTube comedy videos with production company Maker Studios.

"Epic Rap Battles of History" (youtube.com/ERB) emerged out of an improv game the two--who cite rappers like Pharoahe Monch, Wu-Tang Clan and Jurassic 5's Chali 2na as influences--were planning to perform at a live show. The pair's second video, an imagined showdown between Darth Vader and Hitler, went viral and grabbed attention from around the world.

Since then, the "ERB" duo has created two seasons of videos featuring more than 30 duels between pairings that range from topical ("Barack Obama vs. Mitt Romney," "Justin Bieber vs. Beethoven") to fictional ("Gandalf vs. Dumbledore," "Batman vs. Sherlock Holmes") to slightly absurd ("Genghis Khan vs. Easter Bunny").

"ERB" recently was featured in the May 19 "Big Live Comedy Show," which kicked off YouTube's Comedy Week, performing "Mozart vs. Skrillex." The performance included a special guest appearance by Skrillex, reviving his cameo from the original video.

And they still have thousands of years of history left to cover. We hear Socrates could be in the mix soon, so stay tuned for Season 3. RedEye caught up with the duo over the phone from L.A. to talk about their early years in Chicago, professional wrestling and trans-dimensional partying.

A lot of your matchups are not necessarily traditional historical pairings. How do you guys come up with the pairings?

Peter Shukoff: There's like this A-list party of historical characters, both fictional and non-fictional. You've got to be pretty cool to get into this party. There's a guy at the door checking.

Lloyd Ahlquist: The characters don't have to be from history, but the characters just have to have an impact on history, whether that's pop culture or not. So, 50 years from now, are people still going to remember "Harry Potter"? Are they going to still remember "The Hobbit"? Our thought is yes, and that makes them sort of qualified. Even people will be like, "Well, Justin Bieber's super poppy, Lady Gaga's super poppy"--yeah they're poppy, but in 50 years you're still going to remember Justin Bieber, you're still going to remember Lady Gaga.

PS: They're cool enough to get into the trans-dimensional party.

Do you pick favorites?

LA: Sure. We try our best to make it so there's no clear winner, but there [are] certain matchups where there's kind of a good guy and a heel. It's almost like a professional wrestling match. There's a hero, and there's kind of a villain. The villain's going to get some good knocks in, but the hero's going to come away looking good.

One thing a lot of rappers have is a neck chain that kind of says something about them. If you guys had chains, what would they be?

LA: We have had a series of chains for some of our characters. When we did Sarah Palin she was wearing a diamond-crusted elephant. When we did Santa Claus, he was wearing a jewel-and-gold-studded chocolate chip cookie. Snoop Dogg as Moses was wearing a platinum-encrusted Star of David.

PS: If I had one personally, it would probably be a pair of green and yellow sunglasses because that kind of accidentally became my trademark in YouTube videos. ... I still have the same $5 pair that I got at the beach.

Hip-hop fans can be pretty judgmental. Do you ever get any criticism from the hip-hop community about what you're doing as comedians?

LA: We've been lucky enough to have the hip-hop blogs and the forum boards, they like it. I think when we first came into the rap battles a big goal of ours was [that] we want to make funny rap songs, but we don't want to parody rap. We don't want to make parodies of rap battles--we want to make actual rap battles.

We don't approach the music from a funny standpoint of "let's see how weird and kooky we can make rap sound." We just try to make good punch lines. If you watch a regular rap battle, they're funny. The rap lines are funny. We just applied that to characters from history. I haven't experienced too much of that hate, which is awesome.

PS: I haven't either, and I think it's [because] we really committed ourselves to taking the musical element really seriously.

Do you guys have any favorite Chicago stuff that you miss or always check out when you're back?

PS: I miss the train, man. I had a song back in the day about the Red Line train that I used to play all over town. I just miss that romantic--I just miss the trains. I love riding on the "L." I love Roscoe Village.

LA: I miss the improv scene there. We do improv out here. The Mission Improvable guys, we have a theater out here, and it all sort of stems from that Improv Olympic community out there. I make sure I always go there ... when I'm ever in Chicago, I always go there and grab a PBR and just watch a show.

3 steps to getting 1.2 billion views

Every "Epic Rap Battles of History" video averages 30 million views on YouTube, and many surpass 50 million. How do Lloyd Ahlquist and Peter Shukoff do it? Ahlquist broke down three elements that have helped "ERB" achieve consistent success.

It's a simple, repeatable idea

Much of "ERB's" long-term success comes from the fact that it's a Web series, not just a viral video. The most successful series generally start with one or two massive hits and then stick to a pattern that works. And in "ERB's" case, the pattern works because the concept is funny, open to almost endless variation and easy to understand. "It's not that hard for me to explain this idea to my dad," Ahlquist noted.