Tia

Tia (ティア), also known as the Other Goddess, is a game adaptation-original character in Sword Art Online: Hollow Realization. Like her sister Premiere, she is a Non-Player Character (NPC), born from the creation of Sword Art: Origin.

Appearance
Tia looks almost identical to Premiere, the only identifying difference between the twins being the absence of Premiere's small mole right under the corner of Tia's right eye. Like Premiere, Tia has blue eyes and short black hair, the latter of which turned silvery white after she initiated the events of the Great Separation. After being found by Genesis, she began carrying a rapier.

Personality
Like her sister, Tia was originally a null NPC, having no pre-programmed responses or behavior. However, after encountering and spending time around Genesis, she began adopting many traits of his attitude, including his belief in survival of the fittest and his disregard for other NPCs. She also developed an intense hatred for other people, due to their openly hostile attitude and contempt towards Genesis.

Hollow Realization
The Other Goddess was first encountered wandering the streets by Kirito. Mistaken for Premiere, she was led outside the Town of Beginnings, quietly minding Kirito's attempts at conversation while they climbed a hill overlooking a vast expanse of land. Staring into the distance, she listened to Kirito's speech on the endless possibilities provided by their world and his desire to experience all of them with everyone. Upon hearing disturbed laughter at that moment, they investigated the source of the sound, finding a player hallucinating under the effects of a digital drug. When the player was forcibly logged out by his AmuSphere, the Other Goddess stated she had no explanation for the phenomenon they had just witnessed.

After the defeat of the boss of the Jeweled Peak Lakes, the Other Goddess was encountered by Genesis, who was furious at the developers for hiding the real boss behind a decoy, and at Kirito's group for defeating it.

Later, the Other Goddess was spotted by Kirito, Klein, and Agil, who stopped for a quick meal at a popular ramen restaurant. Mistaken for Premiere yet again, she was invited to join them. Accepting the offer, she found the food immensely enjoyable but was slightly confused when Kirito suggested having everyone else along to eat with them for the next time.

After Genesis learned of the alterations performed on the Ground Quest, the Other Goddess, who was named Tia by Genesis, assisted him in finding and obtaining the fifth Sacred Stone. When Genesis unveiled his presence and possession of the item to Kirito and Premiere, who reached the dungeon later, Tia revealed herself to them and observed her twin during Genesis's speech. At the end of the speech, she obediently followed Genesis as he departed from the dungeon.

While Kirito and the others were occupied with a barrier in the Kurjiez Desert, Tia was taught how to wield a rapier by Genesis, and thus expressed her gratitude to be of service after dispatching a monster. However, she lost her footing against another monster, thus requiring Genesis to intervene. After the monster was dispatched, they were approached by several orange players, who declared their intentions of settling their grievances with Genesis. At that moment, the Other Goddess intervened, offering herself as their opponent and ordering them to either fight her or flee. When the players decided to withdraw, Tia and Genesis resumed the lesson.

Shortly after the defeat of the boss of the Kurjiez Desert, Tia and Genesis found the instanced location of an encampment holding the sixth and last Sacred Stone. When the NPCs guarding the stone refused to give them the stone without the presence of both Goddesses, the Other Goddess coldly obeyed her master's orders to execute them. When Kirito and Premiere arrived moments after Tia eliminated the last NPC, she emotionlessly explained her actions to them upon their request. After Genesis appeared and taunted Kirito, the Other Goddess reported she had collected the Sacred Stone. When Genesis learned of the requirement to bring both Goddesses to the Temple of Prayers and Kirito refused to comply, Tia was ordered by the former to defeat the latter and seize her twin.

Quickly engaging in combat with Kirito, Tia threatened to kill him if he did not surrender. After several blows, the Other Goddess questioned him on his refusal to attack her, but was confused by his response, and stunned when he asked if her current actions were what she truly wanted. She stood still for several moments after Genesis launched a surprise attack on Kirito that left the latter stunned and open, after which she was forcibly kicked by the former into finishing him. Regaining her composure, the Other Goddess charged at Kirito, declaring she still had something she needed to do. However, at that moment, her blow was intercepted by Asuna, forcing Tia back. When Genesis's attempt to handle Kirito and Asuna failed, the Other Goddess compliantly followed him as they retreated from the area.

Some time later, Tia followed Genesis deep into the Temple of Prayers and waited for Kirito and Premiere. When her sister and the swordsman finally appeared, the Other Goddess stepped forward but was immediately commanded by her master to not interfere. After the greatswordsman was defeated by Kirito, she fled deeper into the temple.

When Kirito and Premiere reached her at the Alter of Prayers, Tia named all the things Genesis had done for her and how his banishment from Sword Art: Origin had left her alone again. In her eyes, the loss and treatment of the first person to care for her confirmed Genesis' opinion that players were despicable people who would want to hurt them. Announcing that they had no need of a world or people who would reject them, she invited Premiere to pray with her and complete the Ground Quest. Seeing that her twin had chosen not to join her, she decided to destroy Ainground by herself, and thus forcibly summoned the Sacred Stones.

As the Sacred Stones floated around her, Tia folded her hands in prayer and teleported from the Temple of Prayers to hover over Ainground. Dispassionately watching the land below her, Tia bowed her head and folded her hands once more to initiate the Great Separation. While chunks of the earth were torn skyward and coalesced amid lightning to form Aincrad, Tia ominously declared Premiere would be unable to fight against her purpose and would become one with her.

However, with her power alone, Tia was only able to construct an incomplete version of the floating castle, leaving much of the earth below intact. Therefore, she began influencing the module coding the destruction of Aincrad to compel Premiere to join her. When that attempt failed due to Kirito's intervention, she rewrote the quest data to force the castle to crash into Ainground, utterly devastating Sword Art: Origin.