Gwendolyn is known to the rest of the Ark.
As is Hultressa's refusal at letting the Brides and Death Hags see her. It is a testament to Hultressa's political power and influence - even as vestigial as it has been up until now -that such a thing has been possible for the past decade and change.
Everyone knows the Hultressa gave birth to a child blessed by Khaine, very much so. To the elves, it is the sort of thing they can sort of sense thanks to their Aethyrically attuned senses compared to humans, even beyond the visual marker of her eyes showing her as someone directly afflicted/blessed by at least one or some of the Gods. She is off, to them. She is taller than she should be, stronger, faster, everything that a growing murderess might need to be as deadly as possible despite their age. It's part of why her Martial Score is fully applied like an adult's would be, despite said age. To those who are actually sort of into the whole being Druchii thing, she is going to stick out unless she is actively utilizing her abilities to remain stealthy. Which, yes, she technically can do. Might risk drawing on her 'blessings' a bit, though. If not, she would be an unattended Druchii child on her lonesome, and generally that sort of thing is not expected to be a thing. Children are precious tools, after all, for war and murder and such things. They'd be expected to have guards if they were nobility, or hard-eyed matrons and masters keeping them from wandering if they are orphans. A single Druchii child, all by themselves? That's extremely suspicious. She'd need at least a few attendant slaves or something around her. Otherwise, Druchii will see a child-shaped being which is distinctly 'different' from regular elves. That gathers attention regardless.
At the same time, after the disaster at Salkalten and the death of Mellis Screamtaker who has dominated the Ark for a very, very long time, everyone is making moves. Sudden, long-prepared, and so on and so forth. Now is the time that ambition and treachery are at their most potentially rampant. People who have laid back for decades or centuries are sitting up, seeing opportunity. Hence why it wasn't so 'strange' for the rest of the Druchii that all of a sudden Hultressa was starting to partake in their greater politicking and intrigue again. Because, sure, she's been stepping back and aside for a long time now, but she's a Druchii, right? A Druchii, nonetheless. And elves have a different interpretation of 'long-term' plans than humans might. And after Salkalten? Massive, major, continual shakeups to the previous existing power structure. Doing things out of character is in-character, for a lot of Druchii, as is doing things in-character that was already in-character.
Of course, none of them actually know precisely what she looks like. They just know certain signs that others similarly 'blessed' by Khaine or other Cytharai might possess.
