To be honest if the Rarithy Growth system was implemented two month earlier St.Paulia would have been my choice for an upgrade but since my Crit Team is almost complete i'll try to get my hands on Aconite.

http://flowerknight.wikia.com/wiki/Aconite

Since it's a Promo Girl do you guys know an easy way to get her?

Her Code is printed in the light novel "Flower Knight Girl - Aconite's Snowy Town"