The series is available to Buy (starting at ~$6.99/season) or stream via subscription. Purchasing the season often allows for authorized downloads within the Prime Video app.
Digital purchase and download options are also available through this storefront. Physical Media Download Thus Spoke Kishibe Rohan 001 mp4
You can purchase the series as a digital download here. The series is available to Buy (starting at ~$6
If you prefer a permanent high-quality copy, released the OVA collection on Blu-ray in the U.S. on July 18, 2023. Episode 001 Content Note 2023. Episode 001 Content Note