Discussion about the FORTRESS race – Dwarves.

Put Ingvar in charge of defending the city, and that’s it! No enemy will get through. He’s a very useful hero. However, despite all this magnificence, I still don’t understand… HOW TO CAST RUNES???? I have tons of resources, I’m playing as Ingvar, with rune magic, and everything seems fine, but the runes are marked in gray, as if I can’t use them. What should I do?:(