How do you keep reserve troops?

[CyberGuy]

I see 2 small boxes next to the default 5 big boxes to put your troops in. However, I keep reading that you can have reserve troops. How can you keep reserve troops?

[azsportsfan]

You have to purchase the skill with runes (Mind tree). Level 1 gets you one reserve slot opened up, Level 2 gets you the second.

Then you can drag troops from your army to the reserve slot(s). Also, you can pick up wandering friendly troops which do not match your current army if you have a reserve slot open. If you keep "like" troops in your reserve, you can then refill the army ranks from those slots.

[CyberGuy]

Thanks.

However, at level 17, I don't have enough magic runes for this ability. I still have to upgrade my order magic to level 3 and distortion magic to level 3. My chaos magic is already at level 3.

[Ryastar]

??????

Reserve costs might and mind runes, and not a single magic rune.