My question concerns whether or not it's possible to get priority, and cast a spell that partially restores one's life total, after exchanging life for card draw using a card like Necrologia or Necropotence. Presumably, these only give you cards during your end step in order to discourage players from using one of the cards they just drew to restore their life total. However, rule 514.3 mentions special circumstances in which the active player gets priority during the cleanup step. I've read the rule, but I don't understand it.
There are several cards, like Relic Ward, that say that you may cast them as though they had flash, but if you cast them any time that a sorcery couldn't have been cast, you must sacrifice the permanent at the beginning of the next cleanup step. Can casting a card with that sort of triggered ability during one's turn set one up to get priority during the cleanup step-- for the purpose of casting an instant that one just drew (eg. using Necrologia) which restores one's life total?
After a spell or ability (other than a mana ability) resolves during an end step (e.g., Necrologia or the "Put that card..." ability from Necropotence), it will still be the end step and players will get priority to cast instant spells (e.g., Renewed Faith) before the end step ends (C.R. 117.3b, 117.1a). Remember that the end step ends only if all players pass in a row while the stack is empty, not just when the stack becomes empty (C.R. 500.2). See also this thread.
The previous paragraph applies to any step in which a player gets priority, not just the end step (C.R. 500.2). This includes a cleanup step if that step gives players priority (C.R. 514.3a).
Also, the triggering of an ability that triggers "at the beginning of the next cleanup step" is one of the ways a player can get priority during the cleanup step under C.R. 514.3a (other examples include Waylay and Thawing Glaciers [C.R. 108.1]). But there are other ways as well. One example is if an ability triggers because a player discards a card during that step (e.g., The Gitrog Monster; see also this thread). Another example is if a state-based action happens during the cleanup step; see this thread.
Do note, however, that if a player gets priority during a cleanup step, that step will be followed by another cleanup step. And another if a player gets priority during that one, and so on, until there's a cleanup step without priority. Then the turn ends. So the active player still has to discard down to maximum hand size that turn, and all the other stuff that happens during cleanup.
There are several cards, like Relic Ward, that say that you may cast them as though they had flash, but if you cast them any time that a sorcery couldn't have been cast, you must sacrifice the permanent at the beginning of the next cleanup step. Can casting a card with that sort of triggered ability during one's turn set one up to get priority during the cleanup step-- for the purpose of casting an instant that one just drew (eg. using Necrologia) which restores one's life total?
The previous paragraph applies to any step in which a player gets priority, not just the end step (C.R. 500.2). This includes a cleanup step if that step gives players priority (C.R. 514.3a).
Also, the triggering of an ability that triggers "at the beginning of the next cleanup step" is one of the ways a player can get priority during the cleanup step under C.R. 514.3a (other examples include Waylay and Thawing Glaciers [C.R. 108.1]). But there are other ways as well. One example is if an ability triggers because a player discards a card during that step (e.g., The Gitrog Monster; see also this thread). Another example is if a state-based action happens during the cleanup step; see this thread.
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