How to build Charlotte?

I know the perfect person to ask for this question.

*Awaits an answer from Nogistune*

I have the same kind of Charlotte but I don't use her since I wanted Bridal Caeda not Bridal Charlotte. I would say just use her own skills for now then maybe put in place for B slot maybe a seal skill like seal def or seal atk then for the seal put atk +3 or atk/def +3. My Charlotte I got from the Legendary Banner, not this one.
I hope that helped some.

Give her First Bite to Lukas so you can have C H E E S E C A K E W I T H L U K A S

every time i have a unit with bad atk but great def/res i make them into special units. dumping atk and raising defensive stat to the top. even using fortress def or res jus to get extra damage off ignis, bonfire or the other 2. her weapon refined gives her and ally +5 def/res after combat, combined with threaten atk makes her harder to kill and just helps her build up special. atk/def brazen can patch up her atk while boosting her defence even further. or u can always use the harmonic lance+wrath combo to always deal +20 damage with special under 75%hp