Lauren

Lauren (ローレン, Rōren) is Leon's lost lover, who first appeared in Dead or Alive 2. A thief of the Silk Road, her dying words to Leon motivated him to enter the Dead or Alive World Combat Championship, to prove to her that he is the strongest man in the world. In some of the games, her name was mistranslated as Rolande.

History
During his travels as a mercenary soldier, Leon met Lauren along the Silk Road in Asia and the two fell in love. Whilst traveling together in a desert, Lauren died of unknown reasons. As Leon held her during her final moments, Lauren mumbled her final words to him: "The man I love is the strongest man in the world."

It's unclear what she meant by this; it could have been a final loving comment to Leon, seeing him as the strongest man in the world. Nevertheless, Leon felt like he had to prove to her that he was the strongest man in the world, so he entered the second and third Dead or Alive Tournament to do so.

Dead or Alive 3
After the third tournament, Leon returned to the deserts. After stopping by a small lake to rest, he was greeted by a vision of Lauren, either her ghost, a mirage or a hallucination created from Leon's lonliness. During this brief meeting, Lauren gave Leon a desert flower, before disappearing into the wind.

Leon seemed to find this vision as a comfort, and possibly a sign from Lauren that he had finally proved that he was the man that she fell in love with, as he didn't join the fourth tournament.

Etymology
It is debatable as to whether the name of Leon's lover is "Lauren" or "Rolande." Due to phonetic difficulties that frequently occur among Japanese voice actors, "Lauren" would undoubtedly be pronounced incorrectly.

In the version of Dead or Alive 2, Leon's English voice actor clearly named the dying woman as "Rolande," however, in Dead or Alive Ultimate, the subtitles clearly state the woman's name as "Lauren," implying that the name "Rolande" is simply a common Japanese mispronounciation that was accidentally foisted on the translators. This makes sense, as Rolande is typically considered a masculine name.

Trivia

 * In the european versions of some games "Rolande" is spelled "Roland".