In .hack//Roots, Haseo is a newbie player to the Online game known as The World. He is an outcast in real life, and not very good at dealing with people. Upon logging into The World R:2, Haseo is attacked by PKs, (Player Killers), and rescued by Ovan, the Guild master of the Twilight Brigade.

Haseo then joins the Twilight Brigade in order to learn more about Ovan. Eventually, after Ovan disappears for an extended period of time, the Twilight Brigade is disbanded and Shino is PKed by Tri-Edge. Obsessed with saving Shino, Haseo continually seeks power, culminating in his journey into the Forest of Pain, a new Lost Ground, where, after confronting another AI Harald, his PC body was transformed.

At that point level 133 and equipped with an arsenal of incredibly powerful weapons, Haseo became the Terror of Death, a PKK, or Player Killer Killer, who hunted down Player Killers. Upon finding them, he demanded information on Tri-Edge; if they failed to give any useful information, which was usual, he killed them. The name Terror of Death was the title given to him by players, as he truly cared nothing for any other player except for Shino.

Around this time, Ovan returns and informs Haseo that Tri-Edge will reappear shortly at the Hidden Forbidden Holy Ground. Haseo attempts to defeat Tri-Edge, but is Data-Drained, returning some time later as a level 1 character with no items or contact info.

(AIDA- a bug in [The World R:2] that when normal players come into contact with this 'bug' they get their data altered/corrupted and if AIDA doesn't just infect the player the player will fall into a coma)
(Ephitaph users- a select few with Avatars used to fight against Tri-Edge and AIDA among other 'bugs' or 'threats')
(Avatar- a total of 8 creatures first seen in the original DotHack where Kite and his friend defeated them all, Avatars are now used by the Ephitaph users to 'delete' the bugs called AIDA or to remove these bugs from infected players, Avatars use a special move called data drain that when used on players with out an Avatar or AIDA inside them they will drop into a coma).

Oboro is selected as one of the ten Iga clan members that will oppose and fight the Kouga. She gains leadership of the clan after her Grandmother, Ogen, dies. Soon to be replaced by Tenzen, who considered her incapable of leadership because of her passive demeanor. If permitted to marry before the peace treaty was lifted, Oboro knows she could have saved many lives, both Iga and Kouga. But since she couldn't, she is forced to be an enemy of her child-hood love, Gennosuke. Oboro is a very peaceful and gentle girl, her reluctence to kill her enemies shows this. She is also selfless and trusting. Some members of her family take advantage of these traits and trick her on occasions, none the less, she still remains loyal and obediant to them. Since she is the Princess, her family refer to her with respectful terms such as "Oboro-sama", but many of them are wary of her and view her as the odd one of the clan.

She is not exceptional in any ninja combat, but does have an eye technique which can strip any ninja of their powers. This eye technique can develop if she has enough hatred in her, and result in mutilating the enemy instead. This was the hidden ability of her eye-technique that very few were aware of, including Oboro herself. She makes the decision to temporarily seal her eyes shut with a potion given to her by Ogen long ago called the "Seven Days of Darkness", knowing that if she saw any of her clansmen attacking Gennosuke, she might be tempted to use her powers against them instead.

As the war between the clans waged on, Oboro was forced to make difficult choices, and overcome the pain of losing the ones she loved. Though she rarely shows it, it has had a huge emotional impact on her, and causes her to mature and come to many realisations throughout the series. Despite her obvious love and devotion for Gennosuke, Oboro has gained the interest of other ninjas too. Tenzen lusts after Oboro and desires to take her for his wife in order to become the true lord of Tsubagakure. Even if he has to rape her to do it - which he attempts at least twice over the course of the series. Koshirou is completely devoted to Oboro and holds romantic feelings for her, however as Tenzen's apprentice he's obligated to follow his sensei's orders regardless of how he personally feels. Gennosuke, however remains Oboro's only love interest.

Oboro is described in the original novel as having "A face that shone as beautifully as the sun" and "Deep, almost-hypnotic, crystal eyes of intensity". Despite being passive, Oboro can be very determined when it comes to the safety of other people, and cares deeply for her clan. She often goes to visit the graves of her relatives as they die to pray for them to proceed into the after life, but since the graves are so distant from each other this is a tiring progress, however Oboro insists she must as it's "Showing them the respect they deserve", and has repeated this process for years since the death of her nurse who was a mother figure to her until she died.