What to do with a spare 5* Nowi

Hey guys,

Since I was not hyped by the Ayra thing, I just did a full summoning round from the new banner. You never know what might happen. That's how I got a Sigurd last time.
And that's how sometimes it can increase the pity rate for "just" 15 orbs.

Anyway, this time no banner unit for free but some (not bad) inheritance fodder (Palla, Felicia, Hana) and a 5* Nowi.

I already built one for my Dragon Emblem team, so I'm wondering what to do with this second one.

Should I save her for inheriting lightning breath + when a new dragon comes up ?

Should I save her for inheriting threaten res ? Who to ?

Should I merge her with my actually built Nowi ?

So many questions.