The Card Caster archetype of magus gets an ability that replaces the normal spellstrike, called Harrowed Spellstrike.
Beginning at 2nd level, a card caster can invest a single thrown weapon with a single touch or ranged spell as part of the spell’s normal casting time. The spell must target a single creature, and the spell’s range changes to match the thrown weapon’s range increment. This ability otherwise functions identically to spellstrike, except it can only be applied to thrown ranged weapons instead of melee attacks.
Now the wording seems to suggest ALL ranged spells, not just ranged touch spells. And this leads to some odd situations. Is it truely all ranged spells? or is it intended to be just ranged touch?
If its all ranged spells then :
Eg. Spellstrike magic missile. Do the cards gain the unerring properties of the spell? or does that make magic missile able to miss?
What about ranged AOE spells like fireball? Since it says it must target a single creature, and fireball targets a single area, would it be castable?
Please try to backup all answers with official rulings. Looking for RAW but would also like to hear RAI.
Best Answer
Maybe to spells like magic missile but no to spells like fireball
The magus archetype card caster special ability harrowed spellstrike says that the touch or ranged spell that's to be invested into the thrown weapon "must target a single creature, and the spell’s range changes to match the thrown weapon's range increment."
Aiming a Spell on Target or Targets says, "Some spells have a target or targets. You cast these spells on creatures or objects, as defined by the spell itself."
I can't know how strictly a particular GM will hew to the text of the special ability harrowed spellstrike. For example, the spell magic missile has the entry Targets: up to five creatures, no two of which can be more than 15 ft. apart, so this GM would rule that, while the spell magic missile totally could target "a single creature," the spell's Target entry is not only one creature, so the spell magic missile would be ineligible. However, I can imagine another GM ruling that the magic missile spell is compatible with the special ability harrowed spellstrike because the spell can be used to target but one creature… then ruling, because the harrowed spellstrike works like the typical magus's supernatural ability spellstrike, the magic missile spell has no effect unless and until the thrown weapon strikes its target: then the spell discharges—the effect of that will be extra damage and little else.
More restricted is a spell like fireball that has no Target entry at all: the spell fireball is solely an area spell so the caster picks a grid intersection—not a creature—and centers the spell's effect there. The spell fireball is absolutely incompatible with the special ability harrowed spellstrike.
Compare these spells to, for example, the spell charm person that has a Range entry of close and the entry Target: one humanoid creature. Combined, this makes the spell charm person inarguably valid for investing into a card caster magus's throwing weapon using the special ability harrowed spellstrike. Those are the kinds of spells a card caster magus's player should be looking for to avoid arguments and disappointment at the table.
I am unaware of the Paizo staff revealing the design intent of the card caster magus archetype's special ability harrowed spellstrike.