- Magic in Heroes 3

Hmm... Prayer is water magic ;) By the way, that's exactly why I usually take water magic.. Because of Prayer, Clone, and mass Cure.

Exactly right :) That was what you call a Freudian slip :)
It was always difficult for me to imagine Prayer, Clone, and Teleport as Water Magic spells, just as Town Portal as an Earth Magic spell, or Chain Lightning as an Air Magic spell :)
In general, the developers' idea is clear — to balance the relevance of the magic schools, but still...
Prayer, Clone, Teleport, and Town Portal are absolute Air Magic spells (in essence), as they directly relate to affecting space or acting through space.
Chain Lightning is a natural phenomenon in the form of a cluster of the fire element and therefore has a direct relation to Fire Magic :)