Problem with one core (neko project)

I have problem with that core because I have the bios request but to nkp II kai the neko project core there not information to bios and i search in https://docs.libretro.com/library/neko_project_ii_kai/ and just appears that core not the neko project and my problem is when I run the core , run fine but in the time when I play a game in japanese the characters in japanese you know あいうえお is disappear and some games appears but not the text complete and the neko project II kai is too heavy to run in the machine when I testing , what can I do?