About skill targeting

[Amasaroz]

I'm pretty new to this game

so about some skill that target "front row enemy" "rear enemy"
for example, Archer's Deep Freeze, if there's no enemy in rear line- this skill is suddenly useless?

[DeathRiver]

It'll target the rear most enemies.
For example: [F] [M] [R]
If the player's troops is at [F] and the player is at [M], Deep Freeze will hit the player.