Milli's Shield is the only shield in-game that has health regeneration on it.
This item refers to Millicent Serene, a person mentioned in the flavor text that unlocks the quest, the creator of the original uncorrupted Felvine, the Fruit of Fertility. Rabine Saturna mentions her several times, especially as such:
...It will be destroyed - if not for our continued safety from the demonic taint, then for the memory of Millicent Serene... Milli...
Patch 1.3.0 (07-Mar-2005): Added.