The hair and eyes are pretty much identical to how he usually draws Chariot. He's modified the cowlick over time but this is the current consistent shape (from all thin to wider) Compare with the one where she's sitting on the throne looking very unamused because she has twintails there. The locks on the sides of her face have the same points in the same places. Also, the twintails split into different strands in the same place. And while the part of the bangs between the eyes differs between the two pics, other pics of Chariot by him have that part looking like this. Hiyake-chan is Chariot, but not all Chariot is Hiyake-chan.