Once the winning heroine design for Mega Man Legends 3 was selected, the character underwent changes to fit in better with the Legends aesthetic. From left to right, the original, various stages in between, and finally the finished design. The character's name also went through various stages, from Lilly to Aero to Sephira, and finally back to Aero.

With Aero's design solidified, work began on her 3D model. The developers shared a three-part-series of blog posts showcasing the creation process, everything from basic shaping to posable humanoid, from textures to the finished product with shading applied.