The Fountain of Youth
'I was told that everyone I'd served with in the military died shortly after I left. (Part 6)'
The Regeneration Core is a remnant of a once huge titan of an entity which existed outside of any given universe. While originally born within a universe, over time it grew and was forced to exist within the multiverse, outside the 'bubbles' of the universe it once called home.
After its defeat and destruction due to a battle with an even larger entity, the Titan sent a compressed seed of memory, energy and material, the Regeneration Core, nineteen and a half billion years into the future, where Ward Shaw (The Sword) existed.