Can you use Zuran Orb in response to a direct damage spell that would otherwise bring your life total to 0? Under the "old rules" I think you could, but with the more modern rules, I see people quote:
104.3b If a player’s life total is 0 or less, he or she loses the game the next time a player would receive priority.
Having last played during the Urza block, this doesn't really answer the question for me...
Here are two different scenarios which may or may not affect priority differently:
1) I'm at 1 life, my opponent casts Lightning Bolt on me. Can I respond using Zuran Orb and sacrificing two lands to stay alive? I guess what I'm asking is if I have the opportunity to put Lightning Bolt on the stack.
2) I'm at 1 life, I cast Earthquake for 3 points of damage to all players (and non-flying creatures). Can I respond using Zuran Orb and sacrificing two lands to stay alive?
Zuran Orb has an activated ability that doesn't have a timing restriction, which means it can be activated whenever you have priority (i.e., whenever you could cast an instant), which includes when a spell is on the stack (i.e., responding to it).
Therefore, you can freely activate the Orb's ability as long as you can pay its cost in response to these spells, and since the stack works with the last items to be put onto it resolving first once everyone passes priority in succession, you will have more life than the amount of damage you're dealt by the time the spell resolves.
The salient point is, you'd lose the game the next time you receive priority if you had 0 life, but if a spell damaging you equal to your life total is still on the stack, you haven't been dealt any damage yet.
I guess what I'm asking is if I have the opportunity to put Lightning Bolt on the stack.
Actually, Lightning Bolt cannot be anywhere BUT on the stack:
601. Casting Spells
601.2. To cast a spell is to take it from where it is (usually the hand), put it on the stack, and pay its costs, so that it will eventually resolve and have its effect. (…)
The rule quoted to you was correct:
704.5a If a player has 0 or less life, that player loses the game.
The trick is to gain life from Zuran Orb BEFORE you lose life from L-Bolt, so you never get at zero life.
As with most everything happening in a game of Magic, you are allowed to 'respond', and 'responses' take effect BEFORE the thing they respond to. So, they cast Lightning Bolt, and you respond with Zuran Orb. Then Orb gives you life. Then Bolt deals damage to you. You never dropped at zero life!
116.7. If a player (…) casts a spell or activates an activated ability while another spell or ability is already on the stack, the new spell or ability has been cast or activated “in response to” the earlier spell or ability. The new spell or ability will resolve first. (…)
For combat damage, the scenario changes a tiny bit since combat damage doesn't go on the stack, right? So I'd have to activate Zuran Orb before the Combat Damage step (i.e. in the Declare Blockers step) anticipating how much damage I'd need to prevent and sacrificing the necessary number of lands before damage is actually assigned?
Correct. The first thing that happens in the combat damage step is assigning and dealing of combat damage. And right afterwards, if your life total is 0 or less, you lose, without ever getting a chance to save yourself. You have to act before the combat damage step.
Please note, that gaining life and preventing damage are very different things. Zuran Orb gains you life, it doesn't prevent damage. This matters because many cards specifically care about one or the other.
On a related note, I assume I'm allowed to tap lands for mana (for an upcoming spell), store the mana briefly in my mana pool, sacrifice the tapped lands to Zuran Orb for 2 life each, and then cast the spell (e.g. Earthquake) with the mana in my mana pool?
On a related note, I assume I'm allowed to tap lands for mana (for an upcoming spell), store the mana briefly in my mana pool, sacrifice the tapped lands to Zuran Orb for 2 life each, and then cast the spell (e.g. Earthquake) with the mana in my mana pool?
That is correct. A land you sacrifice to pay for Zuran Orb's ability need not be untapped (compare Zuran Orb with Betrothed of Fire; see also this thread), and in general, any mana you add (whether by tapping lands for mana or otherwise) lingers until the step or phase ends (C.R. 500.4), which means that in general, after you add mana, you can cast other spells or activate other abilities before you spend that mana on yet another spell or ability in the same step or phase.
104.3b If a player’s life total is 0 or less, he or she loses the game the next time a player would receive priority.
Having last played during the Urza block, this doesn't really answer the question for me...
Here are two different scenarios which may or may not affect priority differently:
1) I'm at 1 life, my opponent casts Lightning Bolt on me. Can I respond using Zuran Orb and sacrificing two lands to stay alive? I guess what I'm asking is if I have the opportunity to put Lightning Bolt on the stack.
2) I'm at 1 life, I cast Earthquake for 3 points of damage to all players (and non-flying creatures). Can I respond using Zuran Orb and sacrificing two lands to stay alive?
Thank you!!
Zuran Orb has an activated ability that doesn't have a timing restriction, which means it can be activated whenever you have priority (i.e., whenever you could cast an instant), which includes when a spell is on the stack (i.e., responding to it).
Therefore, you can freely activate the Orb's ability as long as you can pay its cost in response to these spells, and since the stack works with the last items to be put onto it resolving first once everyone passes priority in succession, you will have more life than the amount of damage you're dealt by the time the spell resolves.
The salient point is, you'd lose the game the next time you receive priority if you had 0 life, but if a spell damaging you equal to your life total is still on the stack, you haven't been dealt any damage yet.
I̟̥͍̠ͅn̩͉̣͍̬͚ͅ ̬̬͖t̯̹̞̺͖͓̯̤h̘͍̬e͙̯͈̖̼̮ ̭̬f̺̲̲̪i͙͉̟̩̰r̪̝͚͈̝̥͍̝̲s̼̻͇̘̳͔ͅt̲̺̳̗̜̪̙ ̳̺̥̻͚̗ͅm̜̜̟̰͈͓͎͇o̝̖̮̝͇m̯̻̞̼̫̗͓̤e̩̯̬̮̩n͎̱̪̲̹͖t͇̖s̰̮ͅ,̤̲͙̻̭̻̯̹̰ ̖t̫̙̺̯͖͚̯ͅh͙̯̦̳̗̰̟e͖̪͉̼̯ ̪͕g̞̣͔a̗̦t̬̬͓͙̫̖̭̻e̩̻̯ ̜̖̦̖̤̭͙̬t̞̹̥̪͎͉ͅo͕͚͍͇̲͇͓̺ ̭̬͙͈̣̻t͈͍͙͓̫̖͙̩h̪̬̖̙e̗͈ ̗̬̟̞̺̤͉̯ͅa̦̯͚̙̜̮f͉͙̲̣̞̼t̪̤̞̣͚e̲͉̳̥r͇̪̙͚͓l̥̞̞͎̹̯̹ͅi͓̬f̮̥̬̞͈ͅe͎ ̟̩̤̳̠̯̩̯o̮̘̲p̟͚̣̞͉͓e͍̩̣n͔̼͕͚̜e̬̱d̼̘͎̖̹͍̮̠,͖̺̭̱̮ ̣̲͖̬̪̭̥a̪͚n̟̲̝̤̤̞̗d̘̱̗͇̮͕̳͕͔ ͖̞͉͎t̹̙͎h̰̱͉̗e̪̞̱̝̹̩ͅ ̠̱̩̭̦p̯̙e͓o̳͚̰̯̺̱̰͔̘p̬͎̱̣̼̩͇l̗̟̖͚̠e̱͉͔̱̦̬̟̙ ̖͚̪͔̼̦w̺̖̤̱e͖̗̻̦͓̖̘̜r̭̥e͔̹̫̱͕̦̰͕ ̗͔̠p̠̗͍͍̱̳̠r̰͔͎̰o͉̥͓̰͚̥s̟͚̹̱͔̣t͉̙̳̖͖̪̮r̥̘̥͙̹a͉̟̫̟̳̠̟̭t͈̜̰͈͎e̞̣̭̲̬ ͚̗̯̟͙i͍͖̰̘̦͖͉ṇ̮̻̯̦̲̩͍ ̦̮͚̫̤t͉͖̫͕ͅͅh͙̮̻̘̣̮̼e͕̺ ͙l͕̠͎̰̥i̲͓͉̲g̫̳̟͈͇̖h̠̦̖t͓̯͎̗ ̳̪̘̟̙̩̦o̫̲f̙͔̰̙̠ ̹̪̗͇̯t͖̼̼͉͖̬h̹͇̩e͚̖̺̤͉̹͕̪ ͚͓̭̝̺G͎̗̯̩o̫̯̮̟̮̳̘d̜̲͙̠-̩̳̯̲̗̜P̹̘̥͉̝h͍͈̗̖̝ͅa͍̗̮̼̗r̜̖͇̙̺a̭̺͔̞̳͈o̪̣͓̯̬͙̯̰̗h̖̦͈̥̯͔.͇̣̙̝
601.2. To cast a spell is to take it from where it is (usually the hand), put it on the stack, and pay its costs, so that it will eventually resolve and have its effect. (…)
The rule quoted to you was correct:
The trick is to gain life from Zuran Orb BEFORE you lose life from L-Bolt, so you never get at zero life.
As with most everything happening in a game of Magic, you are allowed to 'respond', and 'responses' take effect BEFORE the thing they respond to. So, they cast Lightning Bolt, and you respond with Zuran Orb. Then Orb gives you life. Then Bolt deals damage to you. You never dropped at zero life!
The main difference between 'old' and 'modern' rules is the increased flexibility of the stack. See this Thread:
https://www.mtgsalvation.com/forums/magic-fundamentals/magic-rulings/800972-activating-an-ability-in-response-to-casting-an
RULES OF MAGIC :
http://magic.wizards.com/en/game-info/gameplay/rules-and-formats/rules
Please note, that gaining life and preventing damage are very different things. Zuran Orb gains you life, it doesn't prevent damage. This matters because many cards specifically care about one or the other.
Former Rules Advisor
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(The Gamers: Dorkness Rising)
"Any sufficiently analyzed magic is indistinguishable from science."
(Girl Genius - Fairy Tale Theater Break - Cinderella, end of volume 8)
EDID (May 18): Edited.
Sadly the above link is "forbidden".