Your power grants you all the abilities and attributes of an ancient Shard, the ancestors of modern Entities from before they merged into the first Entities and left their homeworld. You are not actually a ancient Shard; you continue being whatever species you are naturally with these abilities and attributes merely being an emulation created by your power.
The abilities this emulation grants you include innate mid-tier brute strength, regen, and durability, the ability to travel to nearby dimensions that aren’t blocked, the ability to safely absorb large quantities of “basic” energies like heat, radiation, and electricity that you can store and release at a later time at a nearly 1 to 1 ratio with only minor energy loss, the ability to see various basic wavelengths for miles in all directions including into nearby dimensions that aren’t blocked, the ability to quickly mentally process and store large quantities of information, the ability to sense and manipulate space-time by a limited degree in a small area around you, and the ability consume and breakdown nearly any type of basic matter for fuel.
You may also study the abilities and attributes of other creatures including parahumans and through these studies replicate those abilities and attributes with your power for your personal use. Though because of the complexity of modern shards and the protections their abilities have against being understood by the unauthorized you’ll struggle to produce abilities this way anymore complex or powerful than that which “The Fragile One” possesses except for basic abilities like heat manipulation that can be considered extensions or evolutions of capabilities you started out with.
This replication and copying ability is accomplished by mentally manipulating the false biology of a simulation your power provides of the ancient Shard your power is emulating to accurately represent an ancient Shard with those abilities.
All the abilities and attributes this power grants is accurately represented in the simulation of the ancient shard this power is emulating. You can manipulate the simulation to a large and precise degree which accurately affects all the abilities your power grants based on the simulation. All alterations to the simulation must be biologically possible for a Shard with your power providing a pseudo thinker power to understand ancient Shard biology.
The simulation also has a total size limit equal to only that of an average modern shard so you can’t just keep growing and adding to your simulated shard in order to have all your abilities derived from the simulation at full power, maximum capabilities, all at the same time you will eventually have to make sacrifices and comprises in your various “builds” of the simulation.
Your true body acts as the equivalent to an entity avatar to the simulation your shard is emulating if you develop the right capabilities in the simulation you'll be able to do anything to your body an entity can do to their avatars.
You must fuel all of these abilities yourself with running out of energy being fatal for you, you start off full on energy and can store as much energy as your actual Shard has the storage capacity for.
With just this power you do not start off with ftl or space travel capabilities, the ability to communicate with modern Shards, or the ability have hosts of your own though you may eventually develop such abilities with the right alterations to the simulation.
If you have taken the negentropy perk the way it manifests for this power is a bit unique instead of just eliminating your need to worry about your energy reserves it provides you a modest passive energy generation rate for your fuel reserves rapid enough to bring you from an empty tank to full in thirty minutes, running out of energy will also no longer be fatal it will merely knock you unconscious for a few minutes.