I could be wrong but this definitely looks like YD's work. He's one of my favorite artists and this looks like his signature style. Regardless if he drew her, she is exceptionally gorgeous.
To my understanding she hasn't had her English name officially revealed in currently accessible stories. The data miners' consensus seems to be Colette at present, so I have tagged her as such. If that changes later, feel free to replace the tag. The current event just labels her as '???', and the Japanese name appears to be 'クレイ'