Aeon Rivals is described as 'Team up with friends, select from an expanding cast of characters and duke it out against invading Celestian monsters. You’ll have to stay on guard if you want to take these beasts down!'. There are six games similar to Aeon Rivals for a variety of platforms, including Windows, Online / Web-based, Mac, BSD and Steam. The best alternative is Stendhal, which is both free and Open Source. Other Aeon Rivals like games are Realm of the Mad God (Free), Blade Hunter (Freemium), Maplestory (Freemium) and Elsword (Freemium).
Elsword is a free-to-play, 2.5D action MMORPG that features real-time action gameplay and includes both player vs. environment and player vs. player modes. There are several playable characters within the game, each with unique backstories and distinct abilities.
La Tale is a free-to-play, massive multi-player, online role-playing game (MMORPG), with classic 2D side-scrolling action. The game features over 40 character classes, each with unique skills and weapons.