...I have something for you, Warrior of Light. During our expedition to banish Sephirot, I came across a certain relic, and I believe it would be put to best use in your hands.
It is an Allagan device of the kind used to store information─in this case, the record of the furious conflict that took place on the shores of Meracydia between the eikon Sephirot and the forces of Allag.
Should you present this tomestone to the verification node outside Triad Control, the node's systems will analyze the various aspects of the conflict and create for you a false eikon against which you can train. Consider it a sort of “mock battle” that presumes a Sephirot who has broken free of his shackles.
If I understand its workings correctly, the node should also be capable of manifesting a far stronger incarnation of the eikon. This would mimic the catastrophic consequences were Sephirot ever to absorb an additional source of energy─say, by defeating another member of the Warring Triad. A compelling challenge for a warrior of your ability, yes?
You need not possess Mistress Krile's knowledge of Allagan technology to begin this particular battle. Simply present the tomestone to the node on the Flagship, and then follow the orb's instructions. I hope the experience brings you valuable insight, Warrior of Light.
As I explained, simply present the tomestone to the verification node on the Flagship. Follow the node's instructions, and you will soon find yourself facing the towering Sephirot once more!