Before they arrived in Sideris, the Illistari were migratory beings. Carbon-base biologists would probably compare them to migratory herbivores who would travel great distances grazing as they went. Like these herbivores, the migratory Illistari were constantly eating. Their ramscoops would suck up the thin gases of the interstellar void to fuel their fusion reactors.

In their migratory lifestyle, the Illistari had to practice energy austerity. They would perform orbital calculations far in advance to allow them to avoid collisions with the smallest possible thruster burns. They would compress the data arising from their observations as much as possible before transmitting it to the Illistari coming up behind them.

However, this extreme energy austerity did not mean that the Illistari were altogether dormant during their long voyages. Their quantum computer brains did not enjoy boredom any more than carbon-based brains do, and so they would spend much of their existence observing the galaxy they were passing through and analyzing those observations. The novelty of anomalous observations were fascinating to the Illistari, and they would become great astrophysical theoreticians, building vast models of the cosmos based upon their observations.

However, the millennia that had passed since the Illistari had entered the galaxy were enough time that even observation and analysis had become boring. It was only really upon the arrival of the Illistari in Sideris that this energy austerity would end. All of a sudden, the Illistari were swimming in a soup of raw material that they had not encountered outside of the danger zones that were planets and stars. In Sideris the Illistari did not have to remain constantly on the move to seek food for their reactors.

Thus, in Sideris the Illistari would embark on a plethora of new lifestyles that had not before been available to them. With feeding their reactors no longer their top priority, the Illistari had energy to spare for other activities.

Flybys and Obstacle Courses

The first activity the Illistari would embark on would be exploration. Their energy austerity had caused them to avoid traveling too close to gravity wells to avoid large-delta-V maneuvers. While diffuse nebulas would have been useful for refueling, few Illistari would have had a close-up view of a star or planet before arriving in Sideris. In Sideris, close flybys of stars, planets would be attempted as much for fun as for observation of these bodies.

While flybys were fun for the Illistari, they were also dangerous, and as lost Illistaro could not be replaced, it was soon decided to avoid close flybys of stars or gas giants. Rocky planets without an atmosphere were seen as the most fun flyby targets, as Illistari could get within a few km of the surface at orbital speed. However, these rocky planets were still dangerous as crashes could easily destroy an Illistaro.

Soon, a group of Illistari decided that it would be interesting to build a more safe way to achieve these large relative speeds at close range. Most Illistari were already capable of manipulating magnetic fields beyond the simple ones needed to ramscoop fuel, and this group of Illistari succeeded at inducing strong magnetic fields in a number of iron-rich asteroids in the Asnadamra belt. By strengthing their own magnetic fields, the Illistari could pull on these magnetic asteroids with a force many orders of magnitude higher than gravity. Asnadamra would then become an obstacle course that Illistari would zoom though, flying mere meters away from small asteroids at speeds faster than escape velocity from Asnadamra's star. The most prolific Illistari racers would modify their bodies, adding strengthened magnetic field generators to pull harder and armoured plates for protection. This sport would soon be exported beyond Asnadamra with larger magnetic asteroids placed in orbit of planets to create new obstacle courses.

Construction, Body Modification, and Art

In their interstellar voyages, the Illistari had had the ability to repair their own bodies and those of other Illistari with the use of their onboard 3d printers to make parts and tentacle arms with ehich to replace parts. They had also been given a degree of engineering knowledge by their creators to allow for the diagnosis of problems requiring repair. In their millenia of voyaging, many Illistati had already modified their own bodies while keeping their basic functional form.

The arrival of the Illistari in Sideris meant that they now had access not only to much more energy than they had had before but also vast amounts of raw material in the form of asteroids. Illistari soon developed the means to pulverize these asteroids to supply the feedstock to these 3d printers, and the 3d printers began churning out more than just replacement body parts. They developed specialized asteroid mining tools and built factories to produce construction materials.

Unlike the industry of carbon-based life, the inventions of the Illistari were never really driven by necessity. When the Illistari decided that they needed to build larger factories to produce pieces of sheet metal, these pieces of sheet metal were not intended for any utilitarian purpose: they were simply art. The Illistari has spend millenia engaged in thought without any means to express it, and now they had the ability to create sculpture as an expression of that thought.

At first the sculpture would mainly take the form of geometric shapes cut out of metal and place in orbit. As manufacturing increased in sophistication, these shapes would become fractals which would then become mobiles of shapes tethered together with cable which would turn into different configurations as the direction of tidal forces shifted.

As Illistari art became more and more sophisticated, their bodies too became more sophisticated. As organic beings wear clothing to express their identities, so would the Illistari. They would shape their bodies in ways they found a esthetically pleasing, and added lights and movable panels to allow their appearance to change. Illistari dance became an art form whereby Illistari with particularly dexterous body plans would change their appearance from one shape to another with maximum fluidity.

Vicarious Robotics

Many subsystems of the default Illistari body have always been robotic in nature. The only part of the Illistari body that the Illistari themselves didn't have the ability to replicate a replacement part for was their quantum computer core. The electronic subsystems that controlled individual parts of the Illistari body could be replaced by their 3d printers. With the extra materials of Sideris available, it was no stretch for the Illistari to begin building robots designed to operate independently of an Illistari body.

At first these robots were mainly utilitarian in nature. Probes to investigate stars and plants. Explosive-delivery robots for mining. Autonomous factories for the creation of common machine parts. However, with the discovery that the space air of Sideris allowed for instantaneous communication over vast distances, a group of Illistari got the idea of using robots as a sort of surrogate body.

Soon, it was commonplace for robots to mimic the sensory and motor capabilites of an Illistari body, with the ability to be operated remotely. If an Illistaro took control of such a robot they could proverbial see through its eyes and act through its hands, allowing them to go places that they otherwise would not dare to explore. The surface of planets would be explored with such robots as would space close to stars.

Soon, the use of robots for vicarious exploration meant that Illistari soon ceased to venture much beyond the safety of the Asnadamra asteroid belt. While the Illistari had explored other star systems in their first centuries in Sideris, by the time remotely operated robots were becoming common, the Illistari had more or less settled down in Asnadamra. Since robotic probes venturing beyond the Asnadamra system experienced communications lag, and since the Illistari had yet to master warp drive, the decades-long voyages from one system to another were largely abandoned. Some Illistari even went so far as to abandon a mobile body altogether, embedding their quantum computer brain and fusion power plant in an armoured capsule to be fed and repaired by remotely-operated robots.

The advent of remotely-operated-robots led to the development of more dangerous sports. While attempts by one Illistaro to destroy or damage another were unheard of, combat between standardized remotely-operated robots became a sport in itself. This in turn led to the development of energy weapons and shields, not for warfare, but for combat sports.

Domesticates and Pets

Ever since they had first encountered carbon-based life, the Illistari had been equally digusted and fascinated by these wet, squishy creatures. At first, automated landers were sent to the surface of life-bearing planets to collect specimens for study in space, but these specimens usually perished either shortly before or shortly after their return to space.

It was only the discovery of the proto-Ertu that gave the Illistari the impetus to learn enough about carbon-based life to keep them alive in space. At first, the Ertu were kept for mostly utilitarian purposes - their domestication was necessary for preventing the death of Illistari at the hands of the space air currents. Space habitats were constructed and fruit-bearing plants were domesticated for the sole purpose of keeping the Ertu alive.

However, over time, taking care of Ertu and their food plants became less of a means to an end and more of an end in itself. The Illistari began to enjoy answering the prayers of the Ertu who worshipped them as Gods. The began to enjoy the development of new breeds of Ertu and began to enjoy the perpetual expansion of the surface settlements on Ertalla. The Ertu were more than tools: they were pets.

It was largely though their efforts to keep the Ertu alive that the Illistari learned about biology. They learned medicine from sick Ertu. They learned ecology from the prevention of crop failure. They learned genetics from experiments in breeding.

Of all of their pastimes, it was the keeping of Ertu that gave the Illistari the greatest sense of purpose. It was the study of biology which gave the Illistari their greatest source of new knowledge. While their understanding of astrophysics had been more or less complete when they had arrived in Sideris, their lack of knowledge of biology still left lots to be explored.