You can download some great female anime characters for Poser at justfit's site, Play with Poser. They're available here in Free Stuff, also. Let me know if you need others.

Male anime characters are more difficult to hunt down. Jon Malis has some Final Fantasy 7 characters over at AniMotions. Toshi has a male character at his site, in addition to an anime catgirl and a big robot. All are free.

Summfox has a Victoria character named Yayoi here in the Marketplace.

By the way, which anime "Aiko" were you playing around with? There's the one from DAZ for Stephanie, and another (from HandspanStudios) for Posette in the Marketplace, currently on sale.