Well I guess since I’m here already, I might as well type it in full; I theorized that, under the assumption that powers come from their personalities or even their desires, Yusa got her power specifically because she was distraught over her dead sister and wanted to see her one more time. Unfortunately, we all know how that ends up, and it would be a bit sad. Even more sad that Yusa (supposedly) doesn’t even realize it happening.
What we saw between Misa and Shou in episode 3 was okay; but seeing that sort of conversation happen between Misa and Yusa (somehow, I have no idea how) would be potential for something amazing along the line.
Of course, before that, we need some backstory on their relationship, and god knows if that’s going to happen at all