This craft essence is currently unavailable on the EN ver.Seaside Luxury is can be purchased from Dead Heat Summer Race! event shop.
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.
Note: No Bond CE's here.
5 Star Servants Tier List
FGO Reroll Tier List
Best Craft Essence
Best Servants [★4]
10M Downloads Campaign
Minamoto No Yorimitsu (Lancer, Summer 2017)
Altria Pendragon (Lancer Alter)
Fate GUDAGUDA Order
Black Holy Grail (The Black Grail)