I was wondering, are mages not supposed to be able to defend towns? I ask this because i trained a few units of mages, and a few custom designed ice based mages, and left them to defend my town thinking they'll do the job. However when the computer attacked my town, only my militia defended! needless to say they got smashed, and afterwards i see my mages sitting outside the town. I thought maybe i was stupid and left them outside so i reloaded, but nup they're happily sitting in my town, just not defending it. Is this right?

Also i see that only the fire staff is able to be 'upgradable' when designing custom units. Why isn't the ice staff able to do the same? This really sucks because i prefer using cold attack a lot more since more units i find are resistance to fire.