The killing rate is not low, it's just inconsistence. The explosion rate of this series seems pretty random. The last episode, everything explodes, even a slight hit is enough (Exia lands on an enemy and it explodes
), and in this episode, some explodes while some don't. I see Exia sliced a Tieren into two and it explodes, and then it slices another in the same manner, but this time only the lower part explodes. Weird