Story is in the pictures, just click through them.

Creator's note: So there is a nice Ciri model, problem is: it's old. Like second or third generation SFM model old. There have been some people who headhacked Ciri's head on Cassie Cage's body, but personally, I don't think that resembles Ciri's body very well.

This, I have headhacked Ciri on Alyx's body. Much better. This is not a model, but a combination of textures, material overrides and a headhack. So before anyone asks: No, I can't share this model. Because it's not a model.

Here is how it's done: Load Alyx by RedMenace and SmugBastad. Apply material override vector3 $color with values 1.1599999666 1.2999999523 2.5 to body, head, legs, arms, pussy, and nails. Headhack Ciri on Alyx's neck. There will be a color seam, also because Ciri's head textures are of lower quality and more rough than Alyx's model textures. You can avoid the seam by how you align other models in your scene so it doesn't show, or get rid of it in post-processing.

There you have it, a glimpse at my workflow. :-)