Pokemon currently Native to Temperus Volcano:
Koffing
Weezing
Vulpix
Growlithe
Arcanine
Slugma
Magcargo
Charmander
Charmeleon
Magby
Magmar
Pokemon Obtainable here via special ways:
Heatran (Bring Magma Stone in your inventory to this area)
Registeel (Bring both Regice and Regirock in your party to this area)
Charizard (bring a Viridian Wing to this area)
Ho-oh (bring Gold Wing to this area)