Artifact-grade weapon, is this power too weak or too strong?

[FrancisBean]

As a "daily" power on an artifact-grade (+3, sentient) weapon, how strong is “As a Bonus Action you can cause the weapon to generate an Anti-Magic Field for 15’ radius centered on the weapon. The field does not affect the weapon bonus, and lasts until the beginning of your next turn. You cannot use this power again until you have completed a Long Rest.”

I'm concerned that it's actually on the weak side for that level of weapon. But I've never seen anything even approximating that effect before, and I'm wondering if there's a reason why. Anybody see a problem I'm missing?

Note: This would only be one of the powers of the artifact, but it's the one which I can't quite evaluate.

As a side piece of fluff, the artifact was created by a nasty lich in my campaign world. The only way to destroy the weapon is to use it to destroy the lich. But when used against the lich, the weapon functions no better than an ordinary piece of steel.

[kazaryu]

its decently strong, but also is somewhat self balancing. the weapons wielder is affected, as are their allies, which means that while it can be extremely potent to be able to suppress magical defenses of an opponent. equally relevant is the fact that any opponents within 15 feet of the weapon wielder are immune to spells and magic cast by your allies. its essentially an equalizer (with the exception of the person with the weapon, who gets to keep their +3 sword).

the upshot being that overall it should be fairly fine. there are situations where it may shine. but outside of those situations its much more of a mixed bag.

[Biffoniacus_Furiou]

What do you want this ability to accomplish? I'd change it to 1/week (i.e. six days to recharge), make it a reaction, and make it last until the end of their next turn. So they can basically only use it once per dungeon crawl or similar outing, use it to automatically stop something bad from happening to them, but then nerf themselves for a turn for it.

[Vorpalchicken]

I think it is fine as is. Note that artifacts are already not affected my antimagic fields as written. Does this momentary field require concentration? Does it count as casting a spell? If not, that along with its bonus action activation helps balance its very short duration.
If the AMF is just exactly the spell then why not simply allow the artifact one daily use of the spell with its normal duration?

[Rukelnikov]

I think its weak for an artifact, if this is its only special ability it should just be regular AMF, no conc (its the item producing the effect not the wielder) 1/LR, or maybe just 1 min duration 1/SR.

To be completely honest, it doesn't feel artifact level IMO. In 3e Moonblades were minor artifacts, my bladesinger wielded a sentient one since level 11, I used this same tactic myself using my own spells, its cool and somewhat flavorful, but not enough to warrant the artifact tag.

If you wanna lean into the anti magic stuff, you could for instance "add the sword attempts to counter the first targeted spell that would affect its wielder 1/SR", no action spent (its the item doing stuff not the wielder). Or give it properties similar to a ioun stone of absorption with a set ammount of spells levels it can absorb each day. And it allows the wielder to cast Dispel Magic 1/SR.

That way you have a suite of abilities dedicated to a single purpose which give the item both flavor and versatility.

[Elenian]

It's fine, balance-wise, but feels a little bit utilitarian and unexciting to me. If it had a radius of seven leagues or created a dead magic zone for a year and a day it probably wouldn't be enormously more useful but would feel much more like a magic-slaying lich artifact of DOOM.

[Unoriginal]

I would at least add an effect that the artifact wielder is not affected by the Anti-Magic Field.

Or even that the wielder is immune to all antimagic effects.

[Bobthewizard]

I like it. One turn seems a little weak to me, but one minute once per day seems a little too strong. Maybe increase the duration to one minute but decrease the frequency to once per week. It would feel more epic, and probably win one boss fight, but shouldn't disrupt the campaign.

Or maybe leave it as is but let it last until the end of your next turn, so the wielder gets two offensive turns out of it. And maybe not use a bonus action. "At the start of your turn, no action required,..." That way it could be an emergency button if the wielder fails their hold/dominate save.

“At the start of your turn, no action required, you can cause the weapon to generate an Anti-Magic Field for 15’ radius centered on the weapon. The field does not affect the weapon bonus, and lasts until the end of your next turn. You cannot use this power again until you have completed a Long Rest."

[Unoriginal]

I like it. One turn seems a little weak to me, but one minute once per day seems a little too strong. Maybe increase the duration to one minute but decrease the frequency to once per week. It would feel more epic, and probably win one boss fight, but shouldn't disrupt the campaign.

Or maybe leave it as is but let it last until the end of your next turn, so the wielder gets two offensive turns out of it. And maybe not use a bonus action. "At the start of your turn, no action required,..." That way it could be an emergency button if the wielder fails their hold/dominate save.

“At the start of your turn, no action required, you can cause the weapon to generate an Anti-Magic Field for 15’ radius centered on the weapon. The field does not affect the weapon bonus, and lasts until the end of your next turn. You cannot use this power again until you have completed a Long Rest."

IMO, it's an artifact, so seeming "too strong" is part of the concept.

What if it cost a bonus action to activate, lasted until the start of your next turn, and needed to be activated at the start of your turn, but it had unlimited uses?

That would definitively make it an artifact that a Lich would come up with.

[J-H]

Only for 1 round? Too weak. For an artifact, it could be an always-on AMF and would be fine.

[Unoriginal]

Only for 1 round? Too weak. For an artifact, it could be an always-on AMF and would be fine.

True, but since the maker was a Lich, they probably didn't want an always-on AMF.

Unless the wielder is immune to the effect, in which case the Lich would very much want it.

[kingcheesepants]

Way too weak for an artifact, compare it to something like Blackrazor which gives, temp HP equal to the max HP of whatever you last killed (if not an undead or construct) and while you have the temp HP you have advantage on everything. It also makes you immune to charm and fright, it also let's you know when there are creatures nearby, it also casts haste (no action or concentration required) once per day. Any of these effects are at least equal to a once a day 1 round anti magic field. Having all of them makes it so much superior to your artifact that it's hardly even fair to group them together.

Or compare it to the axe of dwarven lords. Which gives you the benefits of a belt of dwarvenkind, a sword or sharpness, a dwarven thrower, as well as letting you teleport anywhere underground without mishap once every 3 days, immunity to poison, an extra 60 ft of darkvison, proficiency with a few tools, and a once per day conjure elemental (earth only). As well as some random properties.

In short your magic sword needs to do more to qualify as an artifact. Right now it's very rare just for the +3 bonus and a once a day AMF for a round is a neat trick but hardly worthy of being an artifact's only special property. Give it charges and let it cast counterspell, dispell magic, and globe of invulnerability using those charges and then give the wielder magic resistance and proficiency in arcana and it'll be a bit more in line with other artifacts.

[Mastikator]

IMO I think the antimagic is fine, but it needs some major and minor bonuses as well (found in the DMG). I think an artifact should be a busy magic item.