Paragon is the MOBA (Multiplayer Online Battle Arena) from Epic Games, the same folks who created such smash hits such as Gears of War, Unreal Tournament, Infinity Blade, and Shadow Complex. In Paragon, you'll be able to choose from a growing number of available Heroes (Epic Games has committed to new Heroes every three weeks), who each have their own strengths, weaknesses, personalities, and play styles. Per Epic, "All Heroes have unique abilities and are designed to have certain strengths that they contribute to the match in order to counterbalance one another's weaknesses." In other words, it's a delightful rock-paper-scissors approach, and you're bound to find a Hero that matches your tastes perfectly.
After picking a Hero, you'll jump into a match and begin clobbering aggressive minions, pesky structures, and enemy Heroes, which results in collected experience to improve your own Hero in various different ways, such as bumping up your health and mana. While every Hero is unique, they all include a basic attack, four active abilities, and a passive ability. In Paragon, there are five players per team, and every team has a base where you can heal quickly and regain precious mana. Each side has three lanes (pathways down the map), and usually you'll need to make sure every lane is covered by at least one Hero. There's also a card shop inside the aforementioned base, which is how you stack up items to enhance your Hero. As you play the game more and more, you can expect to collect new cards fairly often, which can give you more options and add variety to your playstyle. For an in-depth description of all the gameplay and how it all fits together, PC Gamer has a terrific article here.
Paragon is scheduled to enter open beta this summer, where it will be free-to-play for everyone. As Epic Games says, "Paragon is designed so that every player can compete and win without ever having to spend money." But if you're just itching to jump into the action right now, you can buy one of the three available Founder's Packs to join the Early Access Season and begin leveling and upgrading characters immediately. Even better, all of your progress will carry over into the game when it officially releases, so you won't have to worry about wiping out any of your hard-earned experience.