What's the difference between Guardian Angel I, II, and III?

Question

Over at Duke Slava's heroic abilities in Might & Magic Heroes VI, I couldn't help but notice that the first 3 versions of the Guardian Angel ability are identical. What's the difference between them?

Is it the number of times I can cast them? I couldn't tell because I haven't had a single battle in which the meter reached full charge.

Answer 1

The varying ranks of Guardian Angel affect not how powerful the effect is, but who it can affect.

Rank 1 = Core Creatures only -- Praetorians, Vestels, and Marksmen.

Rank 2 = Core or Elite Creatures -- Imperial Griffons, Radiant Glory, Sun Crusader

Rank 3 - Core or Elite or Champion Creatures -- any Haven unit.