[Mage Blade]: Spellcasting

[Johnstone]

I suspect you'll end up with Aegis as some kind of subtractive in any system, unless you use it as a D&D magic resistance (roll Aegis to shrug off a spell).

Here's my understanding of what you're currently thinking of:

This (#1):
a) Roll under [Spellcasting skill plus Force minus target's Aegis], then
b) Roll under [Mana plus Skill plus Spellcasting bonus] and use the margin to reduce Drain.

Or maybe this (#2):
a) roll under [Skill+Force] vs. opponent rolls under [Aegis and maybe something?], then
b) roll under [Mana+Skill+your spellcasting bonus] and use the margin to reduce Drain.

Is that fairly close?

#1 is fewer rolls, and yeah, if you have a high Aegis and some forewarning, putting 8 points of Aegis in Fire against the Fire mage actually will make a big difference to his d20 rolls. But do you want the target's Aegis to affect the Mana roll to reduce Drain (in terms of spellcasting MoS bonus)? Or does it just affect the MoS?

Or do you want Aegis to reduce the effects of the spell directly? In which case Spellcasting MoS could be used to bring the spell back up (negating Aegis) or used as a bonus to the Mana roll.

[Lance D. Allen]

What I'm currently thinking of:

Caster: rolls -vs- (Spellcasting + Force) to determine successful casting

Target: subtracts appropriate Aegis from Force of spell to determine effectiveness of spell

Caster: rolls -vs- (Mana + Skill + margin* from spellcasting roll) then uses the margin to purchase Drain reduction effects

The problem with applying Aegis to the caster's roll is largely conceptual. Aegis is a protective aura, not a proactive force. It hovers around you protecting you from magical energies from outside, rather than seeking out those that mean you harm and interfering with them. It's also An effect-based problem. If the caster lays out an area effect spell, your Aegis should protect you, but it shouldn't protect others in the area of effect.

Or do you want Aegis to reduce the effects of the spell directly? In which case Spellcasting MoS could be used to bring the spell back up (negating Aegis) or used as a bonus to the Mana roll.

Now you're thinking in the right direction. I like that quite a bit. If you roll well, you get to choose whether or not you cast more efficiently or more forcefully.

* this could actually be a penalty, with a failed roll

[Johnstone]

Is the spellcasting roll a pass/fail, or is there failed casting mishaps and stuff?
(aside from a penalty to the "soak" roll)

Does my Aegis just reduce the spell's Force, or can I reduce other aspects of the spell instead? Reducing Area of Effect might be too much like defending others with your Aegis, but what if I get hit with a mind-control spell and I want to reduce the duration instead of how powerful it is?

Or does reducing the Force affect all other aspects of the spell?

[Lance D. Allen]

Is the spellcasting roll a pass/fail, or is there failed casting mishaps and stuff?
(aside from a penalty to the "soak" roll)

At this point, it's pass/fail. I'm open to the idea of using the "buy effects" system in the negative, using negative margin to buy detrimental effects, though. On the other hand, while it's more interesting, it certainly adds a whole additional layer of spanking to failure, so I don't know.

Does my Aegis just reduce the spell's Force, or can I reduce other aspects of the spell instead? Reducing Area of Effect might be too much like defending others with your Aegis, but what if I get hit with a mind-control spell and I want to reduce the duration instead of how powerful it is?

Or does reducing the Force affect all other aspects of the spell?

We're starting to edge toward the spell building system, which I'd prefer to handle in a discrete thread, which I will probably start later on today, after I figure out what information is necessary to start that post. I will be referencing some things said by other posters in this thread, as well. For now, I will simply say that reducing the Force will reduce various aspects of the spell.

As the pace of posting has slowed, unless there are specific questions, clarifications or concerns, I think this thread has served its purpose. Thanks Bill, Simon and Johnstone for your comments. Look for [Mage Blade]: Spell Building.