Total War: Arena, an upcoming free-to-play multiplayer-focused installment in The Creative Assembly's strategy game series, is in development, series lead designer James Russell announced during a GDC 2013 talk today.

Russell revealed that the game will feature 10v10 battles, with each player controlling three units. Players will be able to both earn and purchase items in-game. He characterized Total War: Arena as a cross between a multiplayer online battle arena and a massively multiplayer online role-playing game.

"It provides a much richer variety of experience," Russell said of the multiplayer-focused game.

The developer is hoping to gather a large player population, which is part of the reason The Creative Assembly chose the free-to-play model, Russell said. Total War: Arena has been in development about a year.

Russell said that the developer is experimenting with changes to the Total War formula, focusing on changes like manual aim, charges and active firing, all of which are influenced by the MOBA genre. He also characterized it as a response to the three units players will control, as opposed to the 20 units in the "core" Total War series.

"We want Arena to be just as active and skill-based [as previous Total War games]," Russell said. "It absolutely has to be."

The Creative Assembly will be overhauling the damage control in Total War: Arena with a new focus on per-unit damage. Attacks from the left or right may only damage certain units, Russell explained.

"The behavior of individual men is completely automated," he said.

A series of short videos shown at the end of the reveal highlighted a working version of the game in which a player selected and moved individual units using drag-and-drop control.

In response to a question during the Q&A session, Russell said that Total War: Arena is not planned to be set in a fixed time period. The developer will use add-on content to introduce more components to the battlefield, possibly from different time periods.

You can sign up for information about the game's upcoming closed beta tests at the official Total War website.