Hmm..this is a dangerous path. I would have to say yes, the target usually needs to be present. Almost all spells affect a clearly defined target that you must be aware of.
There are two options.
Option 1: There are exceptions such as with Wizard's infallible parry and similar spells.
Option 2: The target must be present when the spell is cast.
Option 2 will rule the spell impossible, or possible the result of research/experimentation.
I do not think it possible to create a CrIg spell that grants you the ability to cast pillum of fire at will. This is covered by the spell Pillum of fire which you can cast at will.
I agree with you. No granting of spell like abilities using Hermetic magic.
After searching the Core rules I was unable to find a single spell whose target is not present at the time of casting. This leans in favour of option 2.
However one could argue that Wizard's infallible parry is basically the simpler parry spell that through concentration can be "cast" every turn. I would in this case still require that the caster is aware of the weapon he wants to deflect. As argued previously.
So after all this I have doubts about the validity of Wizard's infallible parry.
Note that wards explicitly allow you to affect something that isn't there at the time of casting. that's how you can cast a spirit ward it on a room (terram or Herbam), yet have it affect spirits (Vim). (Arm5, pg. 114)
EDIT - and I'm pretty sure the spell you're talking about (ie, ward vs. Swords, essentially) has been canonized somewhere before. Or, it's just the standard "Ward vs. Dirt (base 5), +2 magnitudes for metal, +1 conc = lvl 20 ReTe effect.
The spell we are discussing is not a ward.
If it was then no problem.
The spell is a ReTe effect that allows you to move one object each turn as long as you concentrate.
The question is really is this possible?
Wards do not target the objects they ward against. They target the warded object/person/place. Hence the target of the ward is present when the spell is cast.
There are a few common places applying to every attempt to do a job with ArM5 magic, like "there are many ways to skin a cat" and "not everything goes".
Magically protecting yourself and others from weapons can e. g. be done with various fast cast defenses, with ReTe wards, with Re spells manipulating things to parry with like MoH p.50 Circular Wall of Shields, and with In spells like ArM5 p.136 Shriek of the Impending Shafts giving big bonuses to Defense scores.
All of these have their advantages, costs and weaknesses, which often are discussed at length on this Forum. In the saga, this "magical engineering" is sometimes deplored, as it eats up time especially when spells are cast spontaneously. But it actually is an important feature of the game, once your characters approach their problems flexibly.
Well, "Elemental shift of Earth to Fire" Voice/Mom/Part. Transforms a part of the earth under a target's feet into fire for a brief moment.
So, the target gets flash-fries for a moment, while falling to the bottom of a pit, and then is covered by earth as the fire returns back to it's original form.
Yes, it's a niche.
Convoluted examples like that, and some Muto Vim metamagic for other D:Mom spells.
Mostly I think you'd want your unnatural changes to linger a while. Otherwise, what's the point?
