lady avalon (first ascension) (fate)

The Merlin from Fate/Prototype, in her First Ascension outfit from her Swimsuit Pretender incarnation in Fate/Grand Order.

This outfit is largely her normal attire (as seen in her Second Ascension in Fate/Grand Order Arcade), but differs in some ways. One of the more notable is that her white overlayer ends just above the bust (similar to her Third Ascension in Fate/Grand Order Arcade) and thus lacks the tall, popped collar, making her black halterneck more prominent.

This tag implicates lady_avalon_(fate) (learn more).