I thought something about this image didn't sit well with me, but from what it looks like he referenced a Senshi-stock when making this piece. I know he has a video detailing how he made this using himself for a reference of both characters, but its uncanny how this drawing, and that one stock image line up side by side. Down to the clothing fabric and folds on the skin. unfortunately I can't find the original stock image, I think Senshi removed it after a while because it was temporarily available image, but anyone on Deviantart can easily find the Senshistock, I think her poses are legendary at this point. Take this information for what it is, a rando's opinion on the internet. I'm more of the mind if you use a reference this extensively, you should let people know about it. Feels pretty dishonest.