The most costly of Luka's offensive skillset in terms of SP (at the count of 4), Death Sword Chaos Star is his most powerful technique by far in Chapter 1 (not including the attacks used under the influence of holy energy).
With his sword flashing like a shooting star, Death Sword Chaos Star strikes an enemy 5 times for a great amount of damage. However, this skill's cost level has rendered it situational. In longer fights, expensive skills like this should usually be avoided in favor of maintaining Spirit protection and Meditation. The skill becomes overshadowed in Chapter 2 by the elemental techniques.
This skill replaces Flail Wildly and Death Sword Chaos Star is later replaced by Granberia's signature skill, Vaporizing Rebellion Sword.