It is this gleeful pranksterism, combined with dedication to detail, that has catapulted Epic Rap Battles into the top 15 of YouTube’s most subscribed channels. Of the millions of YouTube creators worldwide, only about 450 have one million subscribers or more; Epic has 7.7 million.

In fact, Epic seems to have cracked the code on how to make reliably popular scripted content. It is the very type of entertainment that YouTube, with its many one-hit wonders, says is relevant to its future.

Still, the pair acknowledge that any channel’s hold on the public is precarious, not least because, as Mr. Shukoff said in an interview, viewers are “very fickle.” The men hope that by giving their fans less — one video every other Monday during their new four-month season — they can keep them primed and interested. They also target fans of other shows like “Hannah Montana,” hoping to bring them into the fold.

So far, the strategy has worked; the average battle is eventually watched 40 million times, with a healthy helping of adolescent boys. Some videos have topped more than 70 million views, including repeated watchings, and sell well on iTunes.

In July, “Barack Obama vs. Mitt Romney,” uploaded in October 2012, became the first YouTube video to be certified as a gold single by the Recording Industry Association of America, after the association started factoring in video streaming last spring. (The association counts 100 views as one sale.)