Creating an MMOG that keeps fickle kids coming back for more has been an elusive goal for many entrepreneurs. And designing two successful ones is almost unheard of. However, that is exactly what Austin, Texas-based KingsIsle Entertainment is endeavouring to do.

The company’s family-friendly Wizard 101 MMOG (launched in 2008) just surpassed the 30-million registered users milestone.

“We had a kooky idea to bring together the Harry Potter wizard school idea with Pokémon, Yu-Gi-Oh! and a Narnia-type feel,” says J. Todd Coleman, KingsIsle’s VP and creative director.

The MMOG, which borrows from the collectible trading card game model, offers customers either subscription or pay-as-you-go options. (Wizard 101 credits are available via pre-paid cards that have distiribution in 65,000 retail outlets across the US, including Walmart and Target.) While KingsIsle is a private company and doesn’t release financials, with subscriptions running at US$9.95 a month and a host of pay-as-you-go micro-transaction options, it’s fair to say Wizard 101‘s revenues have outstripped original forecasts, which were initially based on the game attracting 100,000 users.

With a lockdown on the core eight to 12 demo (equally split between boys and girls), KingsIsle has just gone into beta with its anticipated follow-up Pirate 101.

“It’s nerve-wracking as a studio,” says Coleman. “If you want to take the list of those who managed to follow-up with another successful MMOG hit, you can probably count them on one hand and have fingers left over.”

Pirate101 takes place in the same universe as Wizard 101, but will feature different worlds and perspectives of the same environments. The new game is a “rogue with a heart of gold redemption quest,” as opposed to Wizard’s hero journey, and the creators are looking to capture a similar demographic.

“You see the same universe, but it’s flipped on its head,” says Coleman. “The pirates go places where the snobby wizards wouldn’t deign to.”

With the same revenue model in place, cross promotions on the Wizard 101 site and the initial support of mass-market retailers, KingsIsle is hopeful that it can repeat its first success.

Pirate 101 will officially launch by year’s end. Expect licensing and merchandising deals to follow suit in 2013.

“It’s an obvious area for us to move into,” says Coleman. “It lends itself well to it and it’s something we are very interested in.”