What are mercenaries for?

[Ori_Master]

I have a good few of my spider attack forces, yet when I attack only 6 are used, I also saw that I only have 6 attacking mercenaries...are they linked? Do I need to get my mercenaries up to use more spiders?

[Quina Quen]

There is no link between regular attack units (or supers) and mercenaries. The game will automatically link the most powerful type of troop to the weapons at your disposal. In the instance that you have 6 weapons along with 6 attack units, 6 super attack units and 6 mercs for example, your strike action will be appropriate to having 6 weapons and 6 supers. The other units merely act as cannon fodder, so to speak.

The point of mercenaries though, from a strategic point of view can be to save wasting your UU on training units or untrainable super units (although you will not benefit from as great a multiplier against your weapons - in layman's terms, they are less effective). You must also bear in mind that you can only have a certain percentage of mercs against the number of trained units you have.