unless I'm misinformed about something, Matsuryuu is the official artist for Helena Blavatsky in FGO, so this wouldn't belong in the popular artists draw other copyrights pool.
I guess it's now common for official artists to make a fanbook of characters they're paid to work on?
I don't know if it's common, but Matsuryuu has been doing this since the design of Helena went public. This looks like a second fanbook, since he released one before this.
