there is this one theory someone made about a pair of prisoners music videos paralleling one another and that theory made me want to compare shidou and mahiru's music video together so here are a couple of things i saw in their respective music videos that reminded me of one another visual wise..
1.) In the beginning of mahiru's music video you can see blue feathers falling up above and in shidou's music video, somewhere around 2:20 shows death tags falling from the sky. These objects could represent the people they have killed.
2.) During most of the time in their music videos, their facial expressions are what you would expect from their personalities/characters. Mahiru's expressions in her music video shows her being energetic, giddy, bubbly and what not while shidou's MV shows him being stoic, determined to reach his goal, phony and calm. These two may seem very different from one another but there is one thing they have in common and that is their expression at the end of their respective music video, their faces show shock and disbelief.. maybe its because they have only realized the impact of their actions when the consequences of their actions have gone so extreme there was no way of avoiding it ..
Thats about it! If some parts seem hard to understand please let me know so i can clarify