Half-Filipinos I Know in J-Drama
First is Yu Takahashi who was in Kamen Rider Kiva as Yuri Aso. I guess not so many people discover she's born from a Japanese father and a Filipino mother. Even I didn't expect it due to her slight resemblance to Vivian Hsu. So yeah, there's one.
The second is Sayaka Akimoto who's obviously half-Filipino (and she does strikingly resemble Lovi Poe from the Philippines). I haven't seen her in any J-Drama yet so I can't comment on her acting.