User blog comment:Mich, Michele & Kuhla/Future Units Preview/@comment-26957321-20160131080215/@comment-139.255.58.50-20160202044216

In fact, Lucina has situational role for certain case as sub unit. It does't mean she is useless as *7.

You can put her with Orna so you can get 4 elements + regular power buffer except spark buff.