Name: Tifa Lockhart (ティファ・ロックハート),
First appearance: Final Fantasy VII
Creator: Tetsuya Nomura
Weapon/ability: Martial arts (and a glove)
Tifa is the childhood acquaintance of the video game Final Fantasy's main protagonist Cloud Strife. They both grew up in the small town of Nibelheim and though they lived next door they were not really close - especially not since the time when the two of them were involved in an accident which gave Tifa a concussion and she remained unconscious for some time and her father blamed Cloud. Cloud then decided to leave Nibelheim to become an elite soldier, before he leaves she asks of him to come and rescue her if she ever would get into trouble.
But Tifa is not a sweet girl just sitting around at home, doing nothing. She learns martial arts from the expert Zangan and acts as a guide in the mountains. All is going well for her until the main villain of the game, Sephiroth completely loses it and decides to burn down Nibelheim. He succeeded and many of the inhabitants, Tifa's father included, is murdered. Tifa is enraged by this and tries to take Sephiroth down herself - and is nearly killed herself in the process. Cloud is there and saves her - but this she doesn't remember herself.
Having lost both home and family (Tifa's mother died when she was little) she moves to the big city of Midgar and opens a bar there, 7th heaven, with an underground resistance-group in the vicinity too, the Avalanche. It is after this she was more meets Cloud, who apparently has left his elite force after becoming one of the first ranked. He is somewhat disoriented and confused and Tifa is worried about him and persuades him to join Avalanche. This is the beginning of their adventure to safe the world - though they are not aware of this to start with.
Tifa appears in several of the follow-up games to the massive hit Final Fantasy VII. This includes the movie Final Fantasy VII - Advent Children, set two years after the game - in which Tifa once more has a bar, but also takes care of children orphaned after the near-destruction of the world.
Tifa was designed by Tetsuya Nomura with concept art by Yoshitaka Amano - as can be seen here. She was not included in the first drafts of the game, but was later added as a key-figure and a contrast to the other main female character, Aerith. This is shown both in clothing (Tifa has a short skirt, initially there was a debate if she was to have a skirt or shorts, and Aerith a long dress) and their personality - Tifa has a lot of emotions too, but she spends most of her time hiding them and is rather shy.