Is it possible for a caster to ready an offensive spell, then cast it when another caster begins to cast a spell, resulting in a damage based concentration check?
Arguments for allowing it: 1)if you have somatic and or verbal components, you could start them and just do them slowly/halt before the end. Do they have to be done at a certain cadence?
2)ready action helps gather and focus your energies so it gets complete before your opponent's spell can be.
Arguments against: There has to be a certain cadece/timing in the somatic/verbal components and there for, the casting time is non-negotiable.
I think it should be allowed, but I wanted to get other peoples opinion.
Thanks in advance,
Physicswolf
As long as the spell requires a standard action or less to cast, yes it's possible.
I think this problem requires a two-prong approach, one prong being realism and the other being game-balance.
Considering realism, I would think that any spell with a casting time equal to the time it takes to swing a sword should be fine; that would mean any spells with a casting time of 1 free action (or 1 immediate/swift action if you use those rules) should be realistic. This would include spells enhanced with the Quicken Spell feat and its variations. Any spell that requires 1 standard action would seem, to me, to take too long.
Considering game-balance, I look to the ability of a fighter to ready a standard attack, which includes a 5 foot step. This would seem to imply that the game-designers wanted the ready action to be very powerful, perhaps so that it will actually see use in the game. If a fighter can ready a 5 foot step and then make perhaps four attacks (considering bonus attacks triggered by feats such as Cleave and Improved Trip); and still get attacks of opportunity, it seems unbalanced to prevent a spell-caster from casting a 1 standard action spell.
After re-reading the section on readying in the PHB, I see that the Ready action to ready "a standard action, a move action, or a free action." --PHB, p.160 The PHB goes on to say, "You can ready an attack against a spellcaster..." and "You may ready a counterspell against a spellcaster...", c.f. the same source and page.
I would conclude that the rules permit any spell with a casting time of 1 standard action (or less) to be readied. If you can ready it as a counterspell, and you could ready it to cast in response to a trigger other than a spellcaster, then I would think you could ready it to "attack" a spellcaster to disrupt his concentration.
I still think this is unrealistic, and I would discourage it in my game with a house rule limiting it to only spells that require a free action (or a swift/immediate, of course. However, D&D is a game, not a simulation of reality, so I wouldn't fault anyone that allowed casters to ready spells with a standard action casting time.
If you don't change how you describe the casting of a readied spell then I would definitely have a hard time describing one magic missile spells interrupting another as an interrupt. However if you use the declared readied action to describe gathering energies and components, clearly prepared to finish the spell in a moment's notice than I think those narrative concerns fade rather quickly. I think of it like a spellcasting equivalent to drawing a knocked bow and training at your proposed target or group of targets (telegraphing your readied action somewhat but also making it clear that it is on the verge of happening. Treating readied actions as not on the verge of happening before their trigger I think narratively falls in to the category of delaying an action. Another good example of a readied action is preparing a spear attack for a charge, the charging creatures would likely see that the spear wielder was prepared for a charge. A critical piece of any readied action is that it's quite specific what sort of action you plan to take is (specific spell, spell like ability, weapon strike, etc.)
Is it possible for a caster to ready an offensive spell, then cast it when another caster begins to cast a spell, resulting in a damage based concentration check?
Yes.
Arguments against: There has to be a certain cadece/timing in the somatic/verbal components and there for, the casting time is non-negotiable.
When you find where that is supported in the rules, let me know. :)