Many skills (most notably curses and auras) apply effects within a radius. Skill descriptions specify radius in yards, while internally it is specified in sub-tiles: each sub-tile is a 2/3 yard by 2/3 yard (2 foot by 2 foot) square, although due to the game's isometric graphics these are rendered as rhomboids.
Radial effects apply to any applicable unit centered over sub-tiles within displayed radius; if missiles spawn within radius, effects apply to target when it collides with missile.
Radius often increases with skill level, but this is not true of the following: