The mages of Ironfang Keep are a real mystery. Originally Ironfang Keep was a "hands off" location because of a planned computer game tie-in that ended up be located somewhere else, but we'd already hinted that it was a mysterious, shunned place whose magic-using inhabitants had to be of VERY great power (to make Mulmaster, Zhentil Keep et al just go away and not keep trying ton conquer them; the inhabitants had to be SO powerful that they could casually 'scare off' Manshoon, Fzoul, and so on). 'Mages who dabbled in plane-hopping activities' was a view advanced later, to support the then-not-yet-quite-published Planescape line. I had always used them as "beast experimenters" who from time to time, at random and totally without warning, would magically 'swoop' and collect dragons, orcs, dragon turtles, terrasques...whatever.