I agree that "Death" and "Undeath' should be distinct. In fact, I generally see them as opposed. This opinion has been expressed by others in
this thread on "Organizing the Spheres".
As Death is often the sphere where a god will absolutely make sure nothing interferes with someone's death and travel to the underworld.
Which is how it currently plays out, in Vanilla. Necromancers only raise bodies, not souls.
I have to disagree with Urlance Woolsbane on this one. I don't see any functional difference between raising the body and raising the soul. Both fall under the heading of "Undeath," and both are equally opposed by "Death," which in this context refers to dead things staying dead and buried. Perhaps we should call it "Funerals" to make that part more explicit?
I usually use 'Wisdom' as a stand-in for 'Magic' and 'Deformity' as a stand-in for 'Monsters', when the concept is specifically the unnatural aspect of the creature (as opposed to 'Animals').
As for Wisdom = Magic... Loki (God of Trickery, Evil, and magic), Hecate (Goddess of Roads, Dogs, Witchcraft, and magic), and Isis.
The whole Wisdom = Magic is more of a bastardization created by giving Wisdom gods magic in other forms of fiction (for example God of War)
I lean more toward IndigoFenix on this one: magic is very diverse, and I don't think collecting all of it into a single "Magic" sphere will work well. I generally see "magic" as something that can be supported by nearly all spheres to one degree or another. That said, I did search the current list of spheres for ones that would likely lead to emphasis on magic (including the effects available from other spheres), and found SCHOLARSHIP, WRITING, SPEECH, TRICKERY, CHAOS, and WISDOM.
Particular examples here would be UNDEATH (the current necromancers and zombies); WEATHER (and all its more narrow child spheres); and FIRE. Possibly also STARS to represent astrology (predicting events by the positions of the planets).
Monsters:As with magic, I see "monsters" as a broad category that can be supported by most spheres to one degree or another. In fact, most magic in the current game is not represented by wizards and spells; it is represented by monsters of various types (animated dead and other night creatures; the various giant animals and animal people; the various inorganic "element men"; titans, FBs, and clowns; the various magma creatures; many of the special creatures of evil surroundings; and more).
Still, I suppose there are a few spheres that might have especially strong tendencies to lead to monsters:
+ UNDEATH (animated dead, including zombies and mummies);
+ MOON (werebeasts);
+ a cluster that includes DEFORMITY, MISERY, NIGHTMARES, and TORTURE (monsters created by deliberate sorcery, likely including night trolls that transform "spouses"; possibly vampires and werebeasts as well, since they are created by divine curses and can spread their curse to others);
+ another cluster that includes VOLCANOES, CAVERNS, and possibly FIRE (the various nasties native to the deep caverns and magma sea);
+ CHAOS, possibly clustered with the "heroism" spheres COURAGE, VALOR, and STRENGTH (powerful monsters that cause lots of mayhem, such as the megabasts, semi-megabeasts, titans, FBs, and maybe demons and angels).