So I have a 5* +spd Eirika and the feathers to promote a 4* +atk to 5*. Which should I use as a base and if anyone has some build ideas, that would be great.
I would say if you are going combat heavy, +ATK helps out her pretty weak stat a bit.
I have a +SPD for more of a generalist/support build as to help prevent doubles and perhaps double average/slow units.
Depends of how you want her to go, I’ll assume offensive from your IV options though so +ATK, to note it’s a superboon and she’s a solid unit all-around, she still has the potential to become quite speedy.
For builds I can only recommend her [Sieglinde (+eff)] and [Hone Spd 4] — I’ll tag @Thehalohedgehog since they can provide the best advice I know about her
+ATK is your best bet for Eirika, her base Attack is pretty bad and she needs all the help she can get. Plus it’s a superboon