Aarhus
There are not really any places in Aarhus which are only specialized in Metal. It can happen that they have Judas Priest or Morbid Angel play live and still the place turns into a dance club afterwards. But anyway, these are the preferred live venues in Aarhus:
Promoter and Metal party organisator based in Århus. From time to time they organize a Metal Café at Café Loco (a very central location, not far from the cathedral). See the website for dates and further info.
This is a small club with some Metal acts, mostly local acts. Check their website for info about the upcoming events.
A new club/bar in Aarhus, they have Metal shows sometimes. Check their homepage for dates & details.
A venue for live gigs - they have also some Metal gigs, check out their webiste for the schedule.