Counterspell/Spell Storing item design

[gnfnrf]

I am trying to convert an item from another system to use in my 4E game. I am treating it as a special kind of item, sort of like an artifact but with an item level and price for the purposes of wealth management. The party in question has just entered paragon tier.

The effect, paraphrased from the other game system, is as follows.

As an opposed test, you can "capture" a spell cast within range, which negates the spell effect and stores it. You can later cast the spell yourself, using your own statistics.

This is my first attempt at the power, roughly sketched out. In other words, I'm not being too careful to phrase everything precisely according for form, here.

Power (Daily, Immediate Interrupt): Trigger. An enemy within 10 squares uses a ranged, area, or close arcane power. Make a Charisma, Wisdom, or Intelligence +4 attack against the target's Will defense. If you hit, the power has no effect, and is captured within the device. You can only capture one power at a time.

Power (Special): You cast the arcane spell stored in the device. Use the action the power requires, the damage dice specified in the power, and the other hit, miss, and effect lines. Use your own Charisma, Wisdom, or Intelligence, and your own implement, feats, and class features to calculate the attack and damage bonus.

If you did not capture this spell in this encounter, this power expends an item daily power usage.

Now, a couple of points.
1.) I know that almost no monster powers are typed arcane. I am prepared to rule on the fly which monster powers are arcane spells and which are not, using common sense and DM fiat.
2.) I know that somewhere out there a power which breaks this horribly. But I am prepared to manage around one or two exceptions, as long as I can see them coming.

So, my questions are, how would you value an effect like this? How likely do you think it is to seriously hurt the game? How would you fix it?

Thanks.

--
gnfnrf

 

[malcolm_n]

Cool concept. Before anything else, I have to suggest removing the stipulation about expending another item daily power. You're already using one to capture the power, letting the other just work is fine and rewards creative use of the item (I capture the medusa's glare and use it later against the vampire lord).

As to the item itself; something like wondrous item 15, 25 wouldn't be bad, with the 25th level getting a +6 to the attack instead. Also, consider adding that you have to be a target of the attack. Finally, I wouldn't require it be an arcane attack, only that it be magical in nature. A roguish monster using a blast attack with knives wouldn't count, but the gorgon's breath might, as would the aforementioned medusa's gaze.

 

[AbdulAlhazred]

Cool concept. Before anything else, I have to suggest removing the stipulation about expending another item daily power. You're already using one to capture the power, letting the other just work is fine and rewards creative use of the item (I capture the medusa's glare and use it later against the vampire lord).

As to the item itself; something like wondrous item 15, 25 wouldn't be bad, with the 25th level getting a +6 to the attack instead. Also, consider adding that you have to be a target of the attack. Finally, I wouldn't require it be an arcane attack, only that it be magical in nature. A roguish monster using a blast attack with knives wouldn't count, but the gorgon's breath might, as would the aforementioned medusa's gaze.

Yeah, but how DO you draw the line between magical and not? Most monsters aren't exactly clearly using magic or not using magic. There's a large grey area there.

As far as valuing the thing? I don't know of a way to equate it to existing items. Its utility is almost totally dependent on how the DM rules what it can and can't work against. Personally I would consider something like this to be an artifact. I wouldn't let PCs make one, it would be a totally unique item that they would have access to for specific story reasons only. The main issue is there's no real good way to balance it against standard items that show up in parcels. Whoever gets it will probably kick butt. Artifacts at least deal with that by never really belonging to the player and bringing along their own plot complications.

 

[Dragongrief]

Yeah, but how DO you draw the line between magical and not? Most monsters aren't exactly clearly using magic or not using magic. There's a large grey area there.

I'd go with Keywords. Make it apply to any attacks with the energy types (fire, lightning, etc) and certain non-energy keywords like illusion. Avoid any of the power source keywords.

So most arcane, divine, psionic and ranged/area primal attacks will qualify, while still leaving out martial attacks. However, should a martial character have the Flaming Blast of Death power, it would be fair game for capture.

 

[Starfox]

In older editions, magic (the equivalent of arcane and divine powers in 4E) was balanced around its limitations. it was generally a bit overpowered, but supposed to be balanced by things like Concentration checks, daily limits on use, etc. This is not the case in 4E. As a consequence, translating old effects that used to be there to balance out the superiority of magic (such as Spell Resistance, counterspelling, dispel magic etc) to 4E requires an entirely new take.

Look at the 4E "Dispel Magic" power - Wizard Utility 10 IIR. It dispels a zone or conjuration - any zone or conjuration, of any origin. If there are any martial powers that produce zones or conjurations (I cannot recall any right of the bat) they are negated by Dispel Magic - "Magic" in the name of the power having basically no meaning at all.

I'd do the same in this case, and not have the power key of origin.