Battery warranties — often 8 years or 160,000km from Japanese manufacturers — are the most valuable part of the deal, and usually transfer to a new owner, but only if the service history is intact.
Warranty terms vary by importer. Some grey-imported vehicles carry a warranty from a local dealer rather than the manufacturer, with different terms and coverage.
Always ask for the original warranty booklet, and confirm the remaining months or kilometres directly with the dealer or service centre before buying — don't take the seller's word for it.
A warranty with no paperwork is not a warranty. Get it verified in writing.