Board Thread:Game Updates/@comment-1820055-20150913021552/@comment-26574811-20150915005606

Archer88 wrote: Know what? I don't care if it needs BP or not. Zuikaku was my first carrier even before I got Akagi from quest. And ever since I got a lucky Shoukaku drop in Spring Event and got her to Zuikaku's level I always sortie them together anywhere, whether it's sorties, event maps or PvP. Not once have I separated them. I can't just leave Zuikaku in the dirt while her nee-san gets all the glory. I'll wait till I'm able to Kai Ni both on the same day.

I think you should simply marry both of them. It looks more like a psychological attachment than a stratigic consideration.