Hikawa was a girl who became Collector for the Alien. Hikawa used to be a nice girl but after being dropped from the competition running team she became desperate and depressed and that would mean she will lose the chance of sports scholarship. After obtaining a coin and getting her wish granted she was able to return to the team but started to transform. If people saw her like that she wont be able to be in the team anymore so she desperately looked for another coin to get another wish and was even ready to kill for it. Source: Gleipnir Wiki