Virtual world company Worlds.com filed suit against City Of Heroes publisher NCsoft on Christmas Eve, claiming infringement on its MMO technology patent.

The main patent referenced in the suit is a "System and Method for Enabling Users to Interact in a Virtual Space."

According to the lawsuit, obtained by the Virtual Worlds News website, Worlds.com alleges that NCsoft's online games, including Dungeon Runners, City of Heroes/Villains and Lineage II, among others, are in violation.

Earlier this month, Worlds.com, which launched in 1994, referenced its holding of patents for two technologies common in virtual worlds and MMOs: scalable chat and user interaction in a virtual space.

As MMO site Massively reported at the time, this theoretically gives Worlds.com enforcement power over just about any online game that lets users talk and interact in a game world -- and the ability to collect financial damages.

Massively's report noted that Worlds.com's interaction patent was filed in 2000 -- after the launch of other games such as Habitat or Ultima Online, which appear to include some reasonably similar features.

The complaint, filed in NCsoft's home ground of the Eastern District of Texas, seeks a permanent injunction against NCSoft operating games covered under the patent, plus damages for the alleged infringement, "in no event less than a reasonable royalty", as well as lawyers' fees.

Worlds.com's second patent, unreferenced in this particular legal claim, is 'Scalable virtual world chat client-server system', which was filed in 1996 and granted in 2001.

[The preceding article by Leigh Alexander also appeared on Worlds in Motion sister site Gamasutra.]