"The Ark" -- how does it work?

[Uh-Nu-Buh]

I have no concrete answers for you, just observations from using it over several battles and trying to determine for myself what is happening.

1. There seems to be a distance effect. It does not cover the whole battlefield, just like 20.

2. Not all units in range are affected, so I believe a savings throw takes place. With that said, most units ARE affected within the range radius.

3. I am unsure. I only have conjecture here, no observable evidence. It would make sense that they have to save every turn or every 3 turns or whatever.