Call me slow and you will not be the only or last one, but there is one way for any civ to get an angel to sacrifice and get a permanent fire elemental. Cast Sanctify on a graveyard (level 1 life spell) and you will get a permanent Host of the Einherjar angel unit. Take it to the Prye and sacrifice for your elemental. Thats a 9 str (+1 fire affinity) 2 move unit for a 5 str one move unit. Not a bad trade IMHO.