I got Kagero!

By which I mean a 5 star OG Kagero, not the flying one, lol. I can't exactly say it was a pitybreaker, since I barely had any pityrate, but still. She's +HP -Def.

So, I have a couple options. I have a +Spd -Def one already, with L&D2/Desperation that I could merge her with. Or I could inherit Poison Dagger+ to my P!Olivia, though she'd only reach 37 Atk, or 42 with L&D3. Right now she hits 50 Atk with Kagami Mochi+, so I don't think I'd get as much use out of it. Otherwise I have a -Atk S!Frederick and a -Spd Jaffar. Should I merge? Inherit? Keep her around until I get someone else?