Thank you! I would probably place a potential son of Regula’s on the city outskirts or somewhere in the inner city, probably trying to protect his own group of survivors. By some means, he would have obtained his father’s gunblade and potentially may have assisted in rescuing the recaptured Svetlana at this point in the rewrite. Since Regula and Varis are roughly the same age, I imagine his son would consequently be the same age as Zenos. However, the revelation of him being Regula’s son and the sword being Regula’s gunblade would be uncovered after the battle against Anima -
An alteration to account for all this would be Svetlana regaining her senses while unsupervised and laments her actions of killing both Gaius and Al-Cid. Having lost the love of her life and succumbing to thoughts of suicide, she steals the gunblade from Regula’s son in order to arm herself. She heads to the palace with one final mission in mind: aid the WoL in their fight against whatever horrors lie within and then leap.
She would navigate the tower using all the survival techniques she learned from Thancred up to that point and arrive with the gunblade during the battle against Anima. Using it against the transformed Varis restores a degree of his sentience, enough to project an image of his former self where he declares his resolve. The phantoms of former officials, Regula included, bear witness to the event and entrust the future to Svetlana as the primal shuts itself down.
Perhaps in spite of all this, she would still try to leap only to be stopped by Thancred. There, he would again promise to keep her safe if she accepts him into her service, which she does. In any case this would certainly give Thancred a more grounded and heroic role as well instead of...becoming atmosphere in Ultima Thule. In hindsight I still can’t believe that zone really happened. Regula’s son would follow soon afterwards and the other characters present would react with shock at the revelation of his parentage, and the true significance of the gunblade. Naturally Svetlana would return it to the son and assign him to work with Jullus on continued rescue efforts around the capitol.
Perhaps another way would have been to tie in the plot surrounding the gunblade and leave Jullus as is except for the surprise revelation of him being Regula’s son towards the end? Given Regula’s association with the Sapphire Weapon...his son having blue hair would not have been outside the realm of possibility.