Due to the ever-increasing number of Photosagnia ostrum on the surface, some seafloor living Photosagnians took a different path due to population separation. As they primarily scavenged for food, the seafloor population became more orientated towards consumption, and so the Photosagnia Rombusi gradually evolved. Having taken a more Rhombus-like shape and developing a primitive low-strength cell wall, the microbes are able to make the most of available space by tightly packing themselves together. This is important for when they feed, as they consume the fungal cores of Binucleid Crystals. They will begin to feed on any exposed mycelium and rapidly multiply, making Colony Crystals and fragmenting Caltrop Crystals a prime target. They are capable of expanding across a crystal's surface until they find a hole through which to consume it's core, often finding an area of exposed root as an entry point. Their cell walls give them limited protection against the digestive enzymes of the crystal shrubs, though many will still be digested, they are small enough to evade detection until their numbers grow large enough to outpace the rate of microbes digested.
Photosagnia Rombusi will continue to feed on every part of the crystal's core that it can reach, multiplying until the entirety of the core has been consumed. This more rewarding lifestyle has allowed them to maintain their rapid multiplication rates despite doubling their size. Once the Photosagnians have consumed every part of their target's core, they will expand until they fill the now empty cavity. As the shell is still capable of photosynthesis, the microbes closest to it will absorb the energy through their cell walls and store it in their cytoplasm, diffusing excess energy through the cell wall to surrounding Photosagnia Rombusi. This primitive colonial lifestyle keeps the entire 'core' of the microbes alive and as such they will continue to multiply as the Photosagnia Rombusi closest to the entry point are forced out. Those that are forced out will drift through the sea, using their now weaker photosynthetic abilities to survive until they land on a Crystal shrub, beginning the cycle anew. As a result of their rapid expansion and consumption, as well as their ability to effectively probe a crystal for openings, these Photosagnians have become a major scourge in the LadyM ocean, where they have already begun to decimate the numbers of the previously untouchable Crystal Shrubs. Despite possessing the same predators as its ancestor, in the Carparmo and Cerberesi, the microbes are not fed on enough by them for their populations to be effectively controlled, as such, their growth has merely been slowed. The Carparmo is now too small to feed on the Photosagnian as effectively, especially with the presence of its cell wall, causing it to take 2-3x longer to feed. The Ceberesi on the other hand, often do feed on the microbes, but their natural inclination to feed on the newly evolved Photosagnia Luculentus, which is very similar to its prior prey, causes them to favour eating them at the surface over Photosagnia Rombusi.