There is no legitimate free version. You have three legal paths:
Many fansub groups prefer W8 because it is thick enough to overlay bright video without needing a heavy outline. Hirakakustdn-w8 Font Free - Download
The search term typically refers to a specific weight or style of the Hiragino Kaku Gothic font family (often mis-typed or truncated). Hiragino Kaku Gothic is a high-quality Japanese Gothic (sans-serif) typeface developed by SCREEN Holdings (formerly Dainippon Screen) and is widely used in macOS, iOS, and Adobe software. The “W8” indicates a Bold weight. There is no legitimate free version
: Before downloading, make sure to check the licensing agreement. Some fonts may have restrictions on commercial use. Hirakakustdn-w8 Font Free - Download
Help you find with a similar weight.