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Rage works under two conditions: if the hero (not necessarily a Barbarian) has the Blood Rage skill, and if the creature has Rage parameters defined in DefaultStats. For example, Wyverns will not work under any circumstances.
Runes can only be applied to creatures from TOWN_FORTRESS and only under the control of a hero with the Rune Knowledge skill. Runes can also be given to creatures as spells. There is another way to give runes to creatures, but it is very specific and rarely useful in real-world scenarios.