Japanese dad is not on my birth cert

So my biological dad is Japanese, but he is not on my birth certificate (my step father is but he is deceased) also we still have contact with him and still visits us here til now, im 21 and I want to know what process should I do for me to be able to live and be a citizen in Japan.

What's your country of citizenship currently?

you can't do anything by yourself. he must make some actions.
but, in general, it may cause serious troubles in his family and relatives in Japan, although you are thinking it so easily.
all you can do is that you ask him.

I'm Filipino

nationality is not a factor for consideration.

There may not be anything that you can do to obtain citizenship for Japan right away, but you might want to contact for consultation:
Citizens�f network for Japanese-Filipino children Inc.(CNJFC)

Best wishes.

although it is how people think about, the best way is that OP makes discussions with him as many times until to get a conclusion.
if OP does not agree with the result, then, OP can ask it to a third person, like an association. but, it may introduce bad relationship between them. it is the final means and probably I think the relationship can't return to the same stage of the previous.