"Aunt, it's because you cannot use qi yet. A normal jade slip usually activates only after using qi, but this crimson one is different.
Correct me if I am wrong, but I am sure it can only be activated by a specific person."
"You are right," Aria confirmed.
To create this jade, the blood of the target was needed, and it was then used as material to carve the formation.
But Edward didn't have any of this; the reason he could make one was because he understood what mattered was using the DNA of the target.
Blood was the easiest, but he also had something else that had Luca's DNA on it.
It was the wedding ring they used. After some time and experimentation, he successfully created the formation to engrave it into the jade slip.
Since MingYue vouched for it, Luca decided to activate the slip. She kept her ability at its peak to make sure she could stop anytime if she saw something bad.