How do defense test against indirect area of effect spells work?

Since there is a defense test against indirect area of effect spells, as pointed out in How do Indirect Area of effect Spells interact with Counterspelling?, I wonder how that exactly works out. Grenades work rather simple with a throwing weapons + agility (3) test without any opposed roll. Now since there is an opposed roll with indirect spells I have a few questions:

1. Is there one opposed roll or multiple ones? I would assume everyone who is affected would get one but that leads to question 2.
2. Does the opposed roll affect scatter? Since this is now an opposed Roll im not certain if the (3) refers to hits or net hits. If it refers to net hits and everyone affected gets a defense roll then how is scatter calculated?
3. What happens to the hits of the defender? Do they only stage damage down? Do they affect scatter? What happens if the defender scores net hits?
4. Assuming the opposed roll affects scatter: Does a person get a defense test if the person is not in the affected area initialy but gets into it through scatter? Does this defense test affect scatter again? I'm asking mainly because this could lead to an extreme chain of dice rolling and really weird results.
5. A very special case: Since indirect area of effect spells have a defense test but grenades do not how does the [Element] Grenade spell work? I would assume like a grenade since it says range touch but I'm honestly not sure. You can find it on page 17 of Shadow Spells.

An example would be highly appreciated especially if it includes counterspelling.

• Interesting question. I'm especially intrigued by the suggestion of odd chains of scatter... Anyone playing a tennis or lacrosse player? ;) Could make a neat little flavour thing in your world. – Nanban Jim Jul 27 '15 at 16:52

1: Each person/critter in range gets a roll to dodge

AoE spells are LIKE grenades in the sense of they have scatter, but unlike a grenade (which only explodes after a # of rounds/turns). Grenades themselves have different rules depending on the type of activation, but that's not the topic here. Ultimately, though, AoE spells happen instantly and grenades do not.

The sidebar example on pg. 283 of the Core Rulebook explains this not-so-well:

This is an Indirect Combat spell, so its damage will be equal to Force 7 + Rikki’s net hits. Ganger 1 is a little out of it and only gets 2 hits. The second ganger is quicker with 4 hits. The three net hits make the total damage hitting the first ganger 10, while the second must attempt to absorb 8 points of damage.

Just like a ranged attack roll, except each person gets a chance to dodge.

2: These roles do not affect scatter

On pg. 283 of the Core Rulebook we get:

Area indirect spells travel from the magician to the point of detonation and then go boom. The test is like that for grenades (p. 181): a Spellcasting + Magic [Force] (3) Test with scatter of 2D6 meters.

So the caster makes the roll and has to beat a threshold of three in order to make it. This threshold can be modified by the GM in certain situations.

If they miss...

Unlike grenades, you get to add your net hits on this test to the Damage Value of the spell, but only if you beat the threshold; otherwise the spell still detonates, but the hits are used to reduce scatter by one meter per hit

3: They aren't hurt

If the defender beats the dodge test, it's just like a normal ranged attack. They jump out of the way, or hit the dirt, or maybe the spell washes over them but doesn't bother them.

If they soak the damage, well...they get hit, but it's soaked, and continue on with the other rules that might apply (catching on fire, etc).

4: Opposed role doesn't affect scatter, so question is moot

Instead of a thrown weapon test you would make a Magic + [Tra- dition Attribute] (3) test instead. Scattered is determined just like grenades. For explosion: