Naomi Kokoro is an invented character by Zelgadis.
She is a character from The King of Fighters Memorial Level 2. For have her you need to unlock her.
How to unlock her ? :
Win with Yukino and Sula versus Krizalid and Sinobu. Then write the password into : "Unlock 2" .
Ending :
We can see her in the ending of the game.She talks to her brother who wants to avenge Gustab.
What did she uses ? :
She use a little sword and do petal with it.

A gif of Naomi