An unnamed Sarkaz woman from the fourth Arknights Integrated Strategies, "Expeditioner's Jǫklumarkar", or just "IS4".
Appears in an encounter node that triggers a battle similar to that of Chained Sarkaz Girls' encounter node from Integrated Strategies 2, "Crimson Solitaire", and an unidentified Cautus from an encounter node in Integrated Strategies(the first one), "Ceobe's Fungimist".