Attea

This picture showcases Attea raw sexuality which she developed by physically maturing during her appearance in Omniverse. Attea is a powerful character who strives to conquer. You show this by displaying her helmet along her with her lingerie. In a warped sense it makes sense that she would seek to conquer her opponent in the bed along with in the battlefield.

Basing her lingerie's color scheme of white and purple on her space outfit is a clever idea as those are the colors she wears in battle. While what is sexually desirable differs person to person, her lingerie would attract any person regardless of their gender or species.

Even her expression shows her key quality: Power. Her lips have a cold smile as her eyes have an analytic expression that probes everyone around her for weakness that she will find and exploit. The confidence in her pose is reinforced by her revealing underwear.

My largest criticism is the lack of a background instead of you settling on a blank back-set. It becomes confusing as there is a reflecting of her heels in the floor. However, since you only have the lower half of her footwear reflected it is not distracting but it could have been removed easily.

Yet this might be a strength of this picture as it leaves the viewer to focus only on Attea in her revealing outfit. Your intention to have Ben10's key female adversary as a seductive tempest is in full display, which makes this picture better in all areas.