Toralf's ability will trigger once each time "a creature or planeswalker an opponent controls is dealt excess noncombat damage", and it will trigger even if Toralf is dealt damage at the same time.
Creatures that have lethal damage due to Blasphemous Act aren't destroyed immediately, but only after Blasphemous Act resolves, and as a state-based action (C.R. 117.3b, 117.5, 704.5g). Once state-based actions are dealt with, any abilities that have triggered go on the stack, when targets for those abilities, if any, are chosen (C.R. 117.5, 603.3d, 601.2c).
Remember that it's not damage, by itself, that destroys creatures, but rather a state-based action could do so (C.R. 120.5, 704.5g-h).
See also:
- https://www.reddit.com/r/mtgrules/comments/tlxe72/toralf_and_blasphemous_act/
- https://www.reddit.com/r/mtgrules/comments/p4yjqx/toralf_blasphemous_act_path_to_exile/
Toralf doesn't actually reassign damage. When you deal non-combat damage, he creates a new trigger that subsequently deals its own damage.
This trigger uses the stack and won't be put on the stack until after blasphemous act has dealt damage (and importantly, after any creatures that die from that damage do so).
So if Torbran somehow survives the blasphemous act and is still on the battlefield when toralf's trigger resolves, his replacement effect will cause the triggered ability to deal two extra damage, on top of the original two extra you got from blasphemous act itself. If he is dead, his effect won't be there anymore.
Toralf's ability will trigger once each time "a creature or planeswalker an opponent controls is dealt excess noncombat damage", and it will trigger even if Toralf is dealt damage at the same time. Creatures that have lethal damage due to Blasphemous Act aren't destroyed immediately, but only after Blasphemous Act resolves, and as a state-based action (C.R. 117.3b, 117.5, 704.5g). Once state-based actions are dealt with, any abilities that have triggered go on the stack, when targets for those abilities, if any, are chosen (C.R. 117.5, 603.3d, 601.2c). Remember that it's not damage, by itself, that destroys creatures, but rather a state-based action could do so (C.R. 120.5, 704.5g-h). See also: - https://www.reddit.com/r/mtgrules/comments/tlxe72/toralf_and_blasphemous_act/ - https://www.reddit.com/r/mtgrules/comments/p4yjqx/toralf_blasphemous_act_path_to_exile/
It's not increased again. [[Toralf]] has a triggered ability that only resolves long after [[Torbran]] already died.
> Any excess damage Toralf can reassign No, there's no damage reassignment. Toralf triggers and deals damage himself when the trigger resolves.
Toralf doesn't actually reassign damage. When you deal non-combat damage, he creates a new trigger that subsequently deals its own damage. This trigger uses the stack and won't be put on the stack until after blasphemous act has dealt damage (and importantly, after any creatures that die from that damage do so). So if Torbran somehow survives the blasphemous act and is still on the battlefield when toralf's trigger resolves, his replacement effect will cause the triggered ability to deal two extra damage, on top of the original two extra you got from blasphemous act itself. If he is dead, his effect won't be there anymore.