Tradition
Disclaimer: I do not own the canon characters of Inuyasha. They belong to Tite Kubo.
Half demons have long been mistreated, abused and even killed for many years. One of the few reasons that some even survived to adulthood was because their powerful sires left ways that if they were worthy the means would show they were strong enough to live. The Dog Demons of the West persistent in breeding with humans found a way for these misfits to be accepted in society. They had to pass a series of trials based on the elements of wind, earth, fire, water and heart. The females also had to survive child birth and mate well. Hanna was the only daughter of a Dog Demon Lord, friend of Inu no Taisho. The friends were close enough that they arranged that their children should be joined in alliance. Hanna's father was Inu no Taisho's vice general third class and even though he bred several times the only female child born to him was from a human concubine. When Hanna passed her trials, her father thought it was time for his daughter to be presented to one of Inu no Taisho's son's: Sesshomaru and Inuyasha. He thought it might be easier for the younger son to accept her and he will offer her to him first.
Hanna stood by her father as the ship that would take them to Japan was readied. She held herself straight as an arrow when inside she was all nerves and worry. She knew within her heart she would never see her homeland again.