>>720484675
Could be Red Shoes. Sixo is working with DEEP, almost confirmed in the latest chapter with Neon following Lyvrin, who was carrying Hammering head in a box, just to find an elevator leading to the deepest part of the Ark, Sector P
D.E.E.P, a lap full of the Ark best scientists, has prayer rooms, so they're 100% connected to the VTC which is where Red Shoes is from
D.E.E.P is working on merging Raptures and Nikkes and the lap is most likely full of Nikkes heads since that what Lyvrin is smuggling to Sixo which is also what Red Shoes secret lap was full of

The only flaw in this theory is the name Sixo, which could be the sixth test subject but Sixo is confirmed a she and high chance she is also a Nikke