User blog comment:JmLyan/Caela, the Voice of Heaven/@comment-24420226-20160212195907/@comment-7709681-20160213145224

@ JmLyan: That's what I thought (and said in a comment), but beyond that: How is she meant to be build? Because I see her as a friendly amalgamation that doesn't decide whether should be a Support or an ADC.

Despite it is true that there are magic pen. options for non AP-champions, beyond the E (Because the Innate's wording seems like she cannot detonate it herself, like Leona) that acts as bonus on-hit damage, there's no build incentive as an ADC, and less as a Support, to build other things than raw AD.

As explained before: As a support, for the the lack of build options for AD Supports, she has little to no offensive or utility scalings. As an ADC, only the E synergizes with the traditional role by fomenting AS and bonus on-hit effects, but other than that is a mage with AD scalings that has few options as the only interaction it has is building the most AD possible.