The Winning Team
Seraphina's life crystal hovered by the blood Essence from the Primordial Red Pheonix. The Energy from the essence could be seen entering the crystal without any resistance.
Rasoul and his subordinate gaze at the occurrence with poppy eyes. They all missed Seraphina, so when they saw the items, they all knew it wouldn't be long before Rasoul revived her.
Under normal circumstances, Seraphina's life crystal will have to mature on it own while developing into a new phoenix. That usually takes hundreds of years. However, Rasoul is different. He has his ways, and one of them is using Necrosmith's ability to create, upgrade, and revive, which is similar to the creation process.
He will need items that have properties similar to those of the dead subordinates. In most cases, he might even choose to add additional items to make the subordinate more powerful after reviving them.