? about Spells and Rage

[Warmskin]

Does anyone use the spells 'Last Hero' (what is the point of having only 1 troop left?) and 'Peacefulness' (seems like a huge trade-off)?
Also, It seems that the spells 'Plague' and 'Shroud' don't work. Shroud doesn't change any stats on the Skeleton Archers I used it on and 'Plague' made no difference to the damage done to some other enemy troops. Is it because they were undead?
And the Rage -'Gizmo', does it matter at all where you place it? It seems pretty useless...
Just a few of the questions I have regarding a thoroughly great game (that needs a better manual) - wish I could read the Russian player made 'help guide'. I know, there's an English version but it's a really bad translation (limitations of the software, I guess). Anyway, any help would be greatly appreciated. Thanks.