The thing with Kira as a villain is that he and Josuke both want the same thing. They are both living their version of a happy and contented life in the town that he loves, until the Shigechi incident clues them both in that the other directly threatens their peace. While they both exist, they both feel trapped and unsafe in their own town. Whoever wins gets to live their quiet life.
That's what the theme song is about. The lyrics apply to both of their perspectives of the other.
My most precious things seem about to be stolen,
By a demon that's burrowed into my everyday life;
My peaceful moments have already collapsed
Being unconcerned, so nonchalant,
Before I even noticed, it'd been torn away...
If I'm gonna get it back, I have to act right away !
With the sharpness of a piercing arrow,
These colliding hearts are a thing of beauty !
I'll chase you anywhere
I'll chase you anytime
You know I'll chase you
There is no escape
Start running, chase you
Again tomorrow, chase you
Until I've kicked your god damn ass
Victory is decided by your tenacity
So I'll chase you