Claim: Introduced in the Japanese anime Mobile Suit Gundam SEED, Cagalli Yula Athha is a fictional character created by Naomi Shindō.
Evidence: Cagalli is voiced by Naomi Shindō in Japanese. 
She has also been featured in a character CDs from the series with tracks performed by her Japanese voice actress, Naomi Shindō. 
Naomi Shindō (Japanese)
Vanessa Morley (English, Ocean)
Cherami Leigh (English, NYAV)