For the normal Ouroboros Serpents, this endless growth of their bodies had a limit, and after Rowan evolved the bloodline to the six-headed Ouroboros Serpent, this limit was pushed back further, and now that he was a Primordial Ouroboros, he could not even see any boundary on this ability.
Even as mortal creatures, his Primordial Ouroboros Serpents could eat till they had the power levels of Primordias. The only drawback was to find meals that could nourish them to such an extent. Unlike normal Ouroboros Serpents, these Primordial Serpents were very selective about what they ate.
Except for beings at the God-Emperor level and above, anything less was treated as thrash. So Rowan could not feed them with any sort of mundane energy or Essence inside the universe.
However, the Primordial darkness inside the Tenebris armor was promising in that regard, and it seemed it was limitless in some regard, and Rowan now had the chance to grow both in knowledge and power.