VERIFIED RECORD
Official record summary
Editorial summary
An effect that reduces Grimoire MP Cost was added in patch 0.12.0.
This entry records a documented change, not a direct quotation or a claim that the line above is the artifact's complete current tooltip. A current-version in-game test will be added separately when it can be reproduced.
How to use this note
Treat it as reliable evidence for the change made in patch 0.12.0. Before planning an exact build around the numbers, compare them with the item tooltip in your current game version.