Electronic Arts ( ERTS) is expanding its realm, agreeing on Tuesday to purchase Mythic Entertainment, developer of Dark Age of Camelot, an online multiplayer game. The move is only the latest in an ongoing effort by EA, the leading video-game publisher, to diversify its products beyond traditional console games. The company has already announced that it plans to sink hundreds of millions of dollars this year into developing online games and titles for mobile phones and handhelds. EA already owns Ultima Online, one of the most popular multiplayer online-gaming titles, and the acquisition of privately held Mythic could help the company as it attempts to tap into the video-game market in China. Because of piracy concerns, game publishers typically don't sell console games in China. Instead, the video games there are largely played online. In addition to Dark Age of Camelot, Mythic is developing a multiplayer online version of Warhammer. "The addition of Mythic to the EA family reflects our deep commitment to the online-gaming market worldwide," Paul Lee, EA's studio president, said in a statement. The companies did not disclose how much EA will pay to acquire Mythic or the form of payment. EA expects the deal, subject to regulatory approval, to close in its second fiscal quarter, which ends in September. Mythic will remain based in its current Fairfax, Va., location after the merger, EA spokeswoman Tammy Schachter said. EA does not expect to lay off any of Mythic's 175 employees as a result of the merger, she said. Instead, EA plans to add employees to the studio, which the company will rename EA Mythic. Shares of EA closed regular trading up 20 cents, or about 0.5%, to $41.41; they were unchanged after the bell.