[ファブリス]

Is there a serif Japanese font common on Android phones that I can target in CSS/HTML?

I'm trying to change the font style on the "mobile" flashcard review page but no luck so far. There is a Japanese font but it's the thick, sans serif one.

For users "hacking" their fonts on the device, do you replace "Droid Sans Japanese" or is there another common font people install?

I use the Motoya fonts which I found out about through one of the Android threads here. It works on Samsung Galaxy devices (no root access needed) and other android devices (with root), but I'm not sure how commonly used they are.

[ファブリス]

Thank you.

Does any Android device come with a Serif Japanese font pre-installed?

I don't think so. At least, there wasn't one on my phone (Galaxy S4), maybe stock android has one.

I think that stock android only comes with a sans serif Japanese fallback font, but I'm not sure, since I don't have root access on any of my android devices.