So In the dungeon journal for Dark Animus it says that he is "empowered by the mysterious substance at the heart of all mogu flesh-shaping experiments." With the 'flesh-shaping' magic the Mogu essentially create life (Sauroks) a practice generally associated with Titans. After seeing this snippet in Dark Animus' dungeon journal I was intrigued. Then I saw images of Ra-Den "chained" in a secret chamber below the room where you fight Primordius. In this chamber you can hardly miss the large vats full of the strange (flesh-like) goo that flows throughout the chamber and into Dark Animus' room. Upon closer inspection of Ra-Den himself I noticed his wounds (arms, leg, eye, most notably the chest). The material underneath the guardian's "stone" skin looks exactly like the goo used in the flesh shaping experiments and the ball in Dark Animus' room. My theory is that this material, essentially Ra-Den's blood, is being harvested and used in conjuction with Mogu magic to create life, as it would make sense that a Titan's blood might have life giving properties.