Board Thread:Warhammer 40k General Discussion/@comment-25618639-20150723053637/@comment-6078851-20150728151439

that's what i meant by saying that until an astartes dies of old age then the false term 'effectively immortal' has a degree of validity: similar to schrodinger's cat - like the cat we know that it's a false premise but it can't be verified until the box is opened (or an astartes dies from old age).

and yeah, a 9 thousand year old astartes could probably wipe the floor with all of us without getting out of breath :P however, the degredation of cells is a basic facet of biology and all living matter is subject to cellular degeneration (even astartes). if something ages (is subject to cellular degeneration) it will die. excluding violent death, and given how healthy dante still seems, i think astartes could easily live up to 10,000 years, maybe even more, but not indefinitely.

chaos marine age can't be compared to realspace or realtime age though - while they spend a lot of time in realspace they also spend an unknown amount of time within warp-corrupted realspace where time doesn't flow the same: abbadon may be technically 10,000 years old but in realtime age he probably doesn't age more than a thousand years or 2. and there's the fact of their many and varied 'blessings' which could also affect how they age.