User blog comment:Gazelleentorch/a question/@comment-4105472-20130325155717

Fei is Kinako's and Asurei's son. However, Kinako died after giving birth to Fei.

At that time, Asurei worked at El Dorado. However, he discovered Fei is a Second Stage Children. As he was working at El Dorado, he could not let them know his own child is a SSC... so he abandoned him.

But Asurei couldn't forget Fei. This one joined Feida, so Asurei did the same and entered Feida under the alias of Helper X, and approached SARU.

To protect Fei while he was with Raimon, Asurei took the young Kinako and brought her to Raimon (which created a time paradox, only Raimon's members who got brainwashed knew her while Tenma&Co didn't.)