Let's say Guardian of the Guildpact is being blocked by a green creature with 3 power; the damage will be prevented by Guardian's protection. So what happens if I cast Test of Faith before damage is declared - does the ToF prevent the damage and add the counters before Guardian's own protection prevents the damage? Or does the green creature not actually deal damage to the Guardian due to its protection? I guess I just don't know the fine print of protection, I know it prevents damage, but is the damage "dealt"?
If two prevention effects would change whether a creature deals damage to Guardian of the Guildpact, the controller of Guardian of the Guildpact decides which one to apply, and the other may or may not still apply depending on whether damage is still being dealt (C.R. 616.1, 616.2, 615.6, 702.16e).
Thus, assuming Test of Faith and protection from monocolored would apply to damage a creature would deal to Guardian of the Guildpact, if the controller of Guardian of the Guildpact chooses the Test of Faith effect, up to 3 damage is prevented and that many +1/+1 counters are given to Guardian of the Guildpact (and then the protection from monocolored effect prevents the rest of the damage [C.R. 702.16e]). But if that player chooses the protection from monocolored effect, all the damage is prevented and no counters are given to Guardian of the Guildpact (C.R. 702.16e).
EDIT: But see the first sentence of comment 3. Further edited after comment 5 was posted.
First, Guardian of the Guildpact can't be blocked by a green creature because of its protection. So let's say it is blocking a green creature.
Your question is about multiple replacement effects. You have two different replacement effects that are trying to modify how the green creature will deal damage. Because you control the relevant permanent(the one being dealt damage) you get to choose how to apply replacement effects. If you choose to apply Test of Faith first it will prevent 3 damage and then put three +1/+1 counters on Guardian. If you choose to apply guardian's own protection first then all the damage is prevented and you can't apply Test of Faith because Test doesn't prevent any damage it won't put any counters on.
To answer your actual final question. Damage that is prevented isn't dealt and won't trigger any "when deals damage" abilities or effects.
Let's say Guardian of the Guildpact is being blocked by a green creature with 3 power; the damage will be prevented by Guardian's protection. So what happens if I cast Test of Faith before damage is declared - does the ToF prevent the damage and add the counters before Guardian's own protection prevents the damage? Or does the green creature not actually deal damage to the Guardian due to its protection?
Test of Faith can't target Guardian of the Guildpact, because Test of Faith is monocolored (white). For that matter, Guardian of the Guildpact can't be blocked by a monocolored creature.
702.16b A permanent or player with protection can’t be targeted by spells with the stated quality and can’t be targeted by abilities from a source with the stated quality.
702.16f Attacking creatures with protection can’t be blocked by creatures that have the stated quality.
Let's replace the Guardian of the Guildpact with Treetop Sentinel and have it blocking the green creature instead.
Then that's up to the Treetop Sentinel's controller.
616. Interaction of Replacement and/or Prevention Effects
616.1. If two or more replacement and/or prevention effects are attempting to modify the way an event affects an object or player, the affected object’s controller (or its owner if it has no controller) or the affected player chooses one to apply, following the steps listed below. If two or more players have to make these choices at the same time, choices are made in APNAP order (see rule 101.4).
616.1a If any of the replacement and/or prevention effects are self-replacement effects (see rule 614.15), one of them must be chosen. If not, proceed to rule 616.1b.
616.1b If any of the replacement and/or prevention effects would modify under whose control an object would enter the battlefield, one of them must be chosen. If not, proceed to rule 616.1c.
616.1c If any of the replacement and/or prevention effects would cause an object to become a copy of another object as it enters the battlefield, one of them must be chosen. If not, proceed to rule 616.1d.
616.1d Any of the applicable replacement and/or prevention effects may be chosen.
616.1e Once the chosen effect has been applied, this process is repeated (taking into account only replacement or prevention effects that would now be applicable) until there are no more left to apply.
616.1f While following the steps in 616.1a–d, one replacement or prevention effect may apply to an event, and another may apply to an event contained within the first event. In this case, the second effect can’t be chosen until after the first effect has been chosen.
If the controller choose to apply the Test of Faith prevention, the 3 damage from the attacking creature doesn't happen, and the Treetop Sentinel gets 3 +1/+1 counters. The protection is then irrelevant.
If the controller choose to apply the protection effect, that damage doesn't happen. Since there is no damage, the Test of Faith is irrelevant at this time.
I guess I just don't know the fine print of protection, I know it prevents damage, but is the damage "dealt"?
The damage that was prevented will not be dealt.
615.1a Effects that use the word “prevent” are prevention effects. Prevention effects use “prevent” to indicate what damage will not be dealt.
615.6. If damage that would be dealt is prevented, it never happens. A modified event may occur instead, which may in turn trigger abilities. Note that the modified event may contain instructions that can’t be carried out, in which case the impossible instruction is simply ignored.
702.16e Any damage that would be dealt by sources that have the stated quality to a permanent or player with protection is prevented.
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Thus, assuming Test of Faith and protection from monocolored would apply to damage a creature would deal to Guardian of the Guildpact, if the controller of Guardian of the Guildpact chooses the Test of Faith effect, up to 3 damage is prevented and that many +1/+1 counters are given to Guardian of the Guildpact (and then the protection from monocolored effect prevents the rest of the damage [C.R. 702.16e]). But if that player chooses the protection from monocolored effect, all the damage is prevented and no counters are given to Guardian of the Guildpact (C.R. 702.16e).
EDIT: But see the first sentence of comment 3. Further edited after comment 5 was posted.
Your question is about multiple replacement effects. You have two different replacement effects that are trying to modify how the green creature will deal damage. Because you control the relevant permanent(the one being dealt damage) you get to choose how to apply replacement effects. If you choose to apply Test of Faith first it will prevent 3 damage and then put three +1/+1 counters on Guardian. If you choose to apply guardian's own protection first then all the damage is prevented and you can't apply Test of Faith because Test doesn't prevent any damage it won't put any counters on.
To answer your actual final question. Damage that is prevented isn't dealt and won't trigger any "when deals damage" abilities or effects.
Test of Faith can't target Guardian of the Guildpact, because Test of Faith is monocolored (white). For that matter, Guardian of the Guildpact can't be blocked by a monocolored creature.
Let's replace the Guardian of the Guildpact with Treetop Sentinel and have it blocking the green creature instead.
Then that's up to the Treetop Sentinel's controller.
If the controller choose to apply the Test of Faith prevention, the 3 damage from the attacking creature doesn't happen, and the Treetop Sentinel gets 3 +1/+1 counters. The protection is then irrelevant.
If the controller choose to apply the protection effect, that damage doesn't happen. Since there is no damage, the Test of Faith is irrelevant at this time.
The damage that was prevented will not be dealt.
GWUBRDraft my Old Border Nostalgia Cube! and/or The Little Pauper Cube That Could!RBUWG
Modern:WDeath & TaxesW | RUGRUG DelverRUG