Kite is the MC of the first .Hack games. He starts his hunt for the virus b/c of his friend who was teaching him about the game and was comatose right in front of him. Aura is an AI. Of course, she's not just any AI but they call her the Ultimate AI. Here's more about Aura:
Aura! She gave Kite the power to use Data Drain, that will help him defeat the indestructible virus and its spawns. He's the only one that could use Data Drain, which made him awesome. Of course, like all RPG games, you run around making friends to make a party of your choosing to defeat the virus. With Kite as the MC, you get four games with him, the fourth being my favorite b/c of the drama. I like drama.

The fighting is okay but can get boring b/c you're doing almost the same thing all the time. Boss battles against viruses, they're called Data Bugs, are long b/c of that shield and once you weaken it, DATA DRAIN breaks it.