And Tuck controlled these Fifth-Rank Sequence Undead precisely through something detected in the "High-Dimensional World": the threads of destiny.
[Sequential Undead] seem like spirits abandoned deep within the Undead Strait Valley... Hm... not seem to be, they are indeed spirits discarded here.
[Sequential Undead] are desperately longing to find their own destinies.
Destiny!
It's a rather abstract and general description.
However, within the threads of the "High-Dimensional World," it takes on a very tangible form.
Tuck could gather and modify these threads of destiny belonging to the Sequential Undead and put them to use.
Sixth-Rank Bishop Level [Sequential Undead] have begun to awaken their own "Undead Consciousness," making their threads of destiny rather fragile, not easy to tamper with.
Whereas the Fifth-Rank [Sequential Undead] lack self-awareness as spirits.
At the same time, they are quite powerful in their own right, so there's no need to worry about one's safety.