This craft essence is currently unavailable on the EN ver.Dive to Blue is can be purchased from Death Jail Summer Escape event shop.
For the duration of "Death Jail Summer Escape" event, this craft essence gains the following effects:
Here is a list of servants & CEs that can be obtained for the duration of the Summer 2017 event part 1: Dead Heat Summer Race and part 2: Death Jail Summer Escape.
Rashoumon event (Ibaraki Douji event)
Murder at the Kogetsukan
Inheritance of Glory
Saint Quartz Farming Guide
Best Craft Essence: Craft Essence Tier List
Nero Claudius (Caster, Summer 2017)
Student Council of the Lunar Sea
Piece of Year 2030 (A Fragment of 2030)
Victor from the Moon