[thejeff]

Nature bless doesn't directly help against Old Age afflictions. What it does is give regeneration which stops hit point loss due to disease. This does not work on sacred units unless you send them into combat & bless them at which point even diseased units will regenerate up to full. Putting a shroud on makes a unit blessed all the time, thus giving them regen outside of battle and stopping hp loss from disease. Putting a regeneration ring on them would do the same thing, but is more expensive.

Again, a better approach for blood nations is Boots of Youth, which stops aging and prevents old age afflictions in the first place.