We know that spells end when you cast another spell with concentration and we know that Draconic Presence's concentration works like a spell. So using Draconic Presence first, then a spell would probably break concentration. 

But if you already had a spell up, you should be able to use Draconic Presence as well. You're not actually casting a spell, you're concentrating on the ability as if you were casting a spell. 

Concentration is concentration. If you are concentrating on one thing and start to concentrate on a second thing, the first thing ends.

The "as if you were casting a spell" part is to clarify this concentration requirement, normally reserved for spells, works the same way for this feature as it would for spell casting.

If you have Draconic Presence up and start casting a concentration spell, or a spell that takes longer than an action, you lose concentration on Draconic Presence causing it to end. If you were concentrating on a spell like Blur then used your Draconic Presence feature you would lose concentration on the spell causing it to end.

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Personally, I would houserule it doesn't use concentration. Combining the effect with concentration spells does absolutely nothing of benefit. There's no broken combo things. All the feature does is make creatures frightened or charmed - which a lot of monsters can either defend against or are immune to, and if they save once they become immune to the feature for 24 hours. Considering this is an 18th level ability, it's not very powerful compared to other end-level stuff and the base class offers nearly nothing for the end levels. I don't see why this requires concentration.

Consider talking to the DM to see if they'd ease or remove this concentration requirement.

Quote from Cyb3rM1nd >>

Concentration is concentration. If you are concentrating on one thing and start to concentrate on a second thing, the first thing ends.

The "as if you were casting a spell" part is to clarify this concentration requirement, normally reserved for spells, works the same way for this feature as it would for spell casting.

If you have Draconic Presence up and start casting a concentration spell, or a spell that takes longer than an action, you lose concentration on Draconic Presence causing it to end. If you were concentrating on a spell like Blur then used your Draconic Presence feature you would lose concentration on the spell causing it to end.

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Personally, I would houserule it doesn't use concentration. Combining the effect with concentration spells does absolutely nothing of benefit. There's no broken combo things. All the feature does is make creatures frightened or charmed - which a lot of monsters can either defend against or are immune to, and if they save once they become immune to the feature for 24 hours. Considering this is an 18th level ability, it's not very powerful compared to other end-level stuff and the base class offers nearly nothing for the end levels. I don't see why this requires concentration.

Consider talking to the DM to see if they'd ease or remove this concentration requirement.

 Do you have anything that can back-up the claim that all concentration acts as spell concentration? I agree that it would end if you used Draconic Presence first, but I can't find anything that says concentration ends when you use a feature that uses concentration. There also isn't anything stating that you can't concentrate on two things at once. 

The only rules about Concentration are in Spells section. Because aside from one or two features, nothing else uses it.

The line in Draconic Presence is to clarify this feature follows those rules despite not being a spell. This means if you had it up and took damage, you make a Con save to maintain it, etc. When it comes to this feature, you treat it the same as you would a spell in regards to concentration. The Spellcasting section has the concentration rules you need to follow.

In the rules of concentration your concentration ends if you start concentrating on something else.

Quote from Cyb3rM1nd >>

The only rules about Concentration are in Spells section. Because aside from one or two features, nothing else uses it.

The line in Draconic Presence is to clarify this feature follows those rules despite not being a spell. This means if you had it up and took damage, you make a Con save to maintain it, etc. When it comes to this feature, you treat it the same as you would a spell in regards to concentration. The Spellcasting section has the concentration rules you need to follow.

In the rules of concentration your concentration ends if you start concentrating on something else.

 Well, that's not what it says in the spellcasting portion. It says that concentration ends when you cast another spell that requires concentration. 

Quote from Colin_Fearfire >>

Quote from Cyb3rM1nd >>

The only rules about Concentration are in Spells section. Because aside from one or two features, nothing else uses it.

The line in Draconic Presence is to clarify this feature follows those rules despite not being a spell. This means if you had it up and took damage, you make a Con save to maintain it, etc. When it comes to this feature, you treat it the same as you would a spell in regards to concentration. The Spellcasting section has the concentration rules you need to follow.

In the rules of concentration your concentration ends if you start concentrating on something else.

 Well, that's not what it says in the spellcasting portion. It says that concentration ends when you cast another spell that requires concentration. 

 
Please, for the sake of my sanity, pay attention to what I write?

The line in the feature is telling you to treat the feature like a spell regarding concentration.

So the rules on concentration apply to the feature as if the feature was a spell. So, casting a spell requiring concentration ends the feature.

Quote from Cyb3rM1nd >>

Quote from Colin_Fearfire >>

Quote from Cyb3rM1nd >>

The only rules about Concentration are in Spells section. Because aside from one or two features, nothing else uses it.

The line in Draconic Presence is to clarify this feature follows those rules despite not being a spell. This means if you had it up and took damage, you make a Con save to maintain it, etc. When it comes to this feature, you treat it the same as you would a spell in regards to concentration. The Spellcasting section has the concentration rules you need to follow.

In the rules of concentration your concentration ends if you start concentrating on something else.

 Well, that's not what it says in the spellcasting portion. It says that concentration ends when you cast another spell that requires concentration. 

 
Please, for the sake of my sanity, pay attention to what I write?

The line in the feature is telling you to treat the feature like a spell regarding concentration.

So the rules on concentration apply to the feature as if the feature was a spell. So, casting a spell requiring concentration ends the feature.

 No, no, I get your assertions. I understand you're saying that because it says to treat it like a spell with concentration, it should end any previous spell with concentration.  

I'm saying that isn't what either of those features are saying. It says "For 1 minute or until you lose concentration (as if you were casting a concentrating spell)," Basically, it only drops under the same criteria that a spell with concentration drops. 

However, it doesn't say you treat the feature as if you *cast* the feature as a concentration spell, you treat it as though you were casting a concentration spell for the purposes of losing concentration. So, it's not acting like a concentration spell until you're looking for the criteria of it being dropped. 

That's odd, when I look the exact quote is this on D&D Beyond,

"For 1 minute or until you lose your concentration (as if you were casting a concentration spell)"

It says as if casting a concentration spell, and we know that when you cast a concentration spell all other concentration spells drop. So, all other concentrations spells should drop. If you want i can post the entire feature and highlight this section, maybe your book has something else written then D&D Beyond?

The line reads "as if you were casting a concentration spell" not "as if concentrating on a spell".

Convenient change you made there. You get I've been here for years and know these tricks, right?

The feature is treating as if you were casting it like a concentration spell and should be goverened by the spell concentration rules.

I cannot be bothered to give you an essay on the English Language to explain context and idiomatic language.

At the end of the day you have the idea in your head of how you want it to work, and you're trying to get all word-twisty to make your way seem the right "well, actually it's like this" way. I'm clarifying what the words on the page mean in the English Language given the context of the feature and the whole book (you must consider the whole source, not just that bit) and since that contradicts what you want it to be, you're clinging to your idea and trying to take things out of context, misquote things and twist the language to get it to work for you. Maybe this is intentional maybe it is not, but it is what you're doing.

I'm more than happy to discuss the feature as a feature and whether I think it should have this concentration requirement or not. But I'm not going down this pointless road of word-twisting. No offence to you, nothing personal it's just I've done this song and dance like five times in the last six or so days, and I'm tired of it.

It doesn't matter what you think it says. It doesn't matter what it actually says. It doesn't matter if the entire staff of WotC came and said "this is how it is" and it doesn't matter if a hundred random DMs came and said "this is how we do it". At the end of the day all that matters is what the DM you're playing with thinks - if they want it to have strict concentration, it has it, if they want it "with loopholes", it will be so, if they want it "no concentration needed" then yays all round. It doesn't matter what the book says, only how they want it to work. So any "oh but with THIS word here it actuall means..." out of context nonsense arguing serves absolutely no point at all. It's a nitpicky, trivial and worthless waste of time.

So, the better question is how do you want it to work, and why?

Quote from 4yulming4 >>

That's odd, when I look the exact quote is this on D&D Beyond,

"For 1 minute or until you lose your concentration (as if you were casting a concentration spell)"

It says as if casting a concentration spell, and we know that when you cast a concentration spell all other concentration spells drop. So, all other concentrations spells should drop. If you want i can post the entire feature and highlight this section, maybe your book has something else written then D&D Beyond?

 I have the book, I just typo'd. Yeah, it says that but it's under the portion where it says "or until you lose your concentration." It being attached to that phrase really just signifies to me that it isn't necessarily saying the entire feature acts as if you were casting a concentration spell, it's saying that the concentration end conditions works the same way as concentrating on the spell. So taking damage, being incapacitated, casting another concentration spell (after the feature is active), or the DM puts you in a perilous situation like an earthquake. 

Quote from Cyb3rM1nd >>

The line reads "as if you were casting a concentration spell" not "as if concentrating on a spell".

Convenient change you made there. You get I've been here for years and know these tricks, right?

The feature is treating as if you were casting it like a concentration spell and should be goverened by the spell concentration rules.

I cannot be bothered to give you an essay on the English Language to explain context and idiomatic language.

At the end of the day you have the idea in your head of how you want it to work, and you're trying to get all word-twisty to make your way seem the right "well, actually it's like this" way. I'm clarifying what the words on the page mean in the English Language given the context of the feature and the whole book (you must consider the whole source, not just that bit) and since that contradicts what you want it to be, you're clinging to your idea and trying to take things out of context, misquote things and twist the language to get it to work for you. Maybe this is intentional maybe it is not, but it is what you're doing.

I'm more than happy to discuss the feature as a feature and whether I think it should have this concentration requirement or not. But I'm not going down this pointless road of word-twisting. No offence to you, nothing personal it's just I've done this song and dance like five times in the last six or so days, and I'm tired of it.

It doesn't matter what you think it says. It doesn't matter what it actually says. It doesn't matter if the entire staff of WotC came and said "this is how it is" and it doesn't matter if a hundred random DMs came and said "this is how we do it". At the end of the day all that matters is what the DM you're playing with thinks - if they want it to have strict concentration, it has it, if they want it "with loopholes", it will be so, if they want it "no concentration needed" then yays all round. It doesn't matter what the book says, only how they want it to work. So any "oh but with THIS word here it actuall means..." out of context nonsense arguing serves absolutely no point at all. It's a nitpicky, trivial and worthless waste of time.

So, the better question is how do you want it to work, and why?

 I actually just want it to work the way it's written. That's the point of this thread. I'm not manipulating the words, I've made a mistake but my point still stands that I don't think concentration ends on a spell when using a feature that has concentration as if it were cast as a spell.

Wording is apparently very important in D&D and sets precedents for what you can and can't do. For instance, a thrown dagger is a ranged attack with a melee weapon but a ranged weapon attack. A bow used to smack someone is a melee attack with a ranged weapon but also a melee weapon attack. But the thrown dagger isn't an attack with an attack with a ranged weapon and the bow isn't an attack with a melee weapon. Another example is that you can't dispel magic magical effects that don't come from spells. Another example is that you can't twin firebolt because you have the ability to target objects. 

It's not like I'm trying to be difficult or whatever. I'm trying to actually get the truth from the wording. I know anyone can rule any way but I'm not looking for anyone's rulings. I'm looking for answers. You've provided what you believed to be the answer but I don't exactly buy your reasoning. 

I'm in neither camp, really. I think the feature is good enough as you interpret it that I'd be fine if the way you interpreted it was how it worked, but I'm looking for something specific that can be applied without being interpreted the way I'm reading it. Something that says "features that end as if you are casting concentration spells also end your concentration." Because the phrase still reads as a parameter for when the feature will end, not when it begins. 

Now that I read it closely, I see your point. Your arguing that "you lose your concentration (as if you were casting a concentration spell)" means that the spell only follows rules that would cause you to lose concentration on this feature, not rules causing you to lose concentration on other spells. Otherwise it would say that the spell follows concentration rules.

Of course, it also says that "You can't concentrate on two spells at once". This might imply that if you tried this, draconic presence wouldn't work since you would be concentrating on two spells. Since the feature follows rules that would cause it to lose concentration, this seems like it would apply as it is a rule that would cause you to lose concentration.

Edited to shorten and clarify, I really do edit my comments too much don't I?

Quote from Colin_Fearfire >>

Quote from Cyb3rM1nd >>

The line reads "as if you were casting a concentration spell" not "as if concentrating on a spell".

Convenient change you made there. You get I've been here for years and know these tricks, right?

The feature is treating as if you were casting it like a concentration spell and should be goverened by the spell concentration rules.

I cannot be bothered to give you an essay on the English Language to explain context and idiomatic language.

At the end of the day you have the idea in your head of how you want it to work, and you're trying to get all word-twisty to make your way seem the right "well, actually it's like this" way. I'm clarifying what the words on the page mean in the English Language given the context of the feature and the whole book (you must consider the whole source, not just that bit) and since that contradicts what you want it to be, you're clinging to your idea and trying to take things out of context, misquote things and twist the language to get it to work for you. Maybe this is intentional maybe it is not, but it is what you're doing.

I'm more than happy to discuss the feature as a feature and whether I think it should have this concentration requirement or not. But I'm not going down this pointless road of word-twisting. No offence to you, nothing personal it's just I've done this song and dance like five times in the last six or so days, and I'm tired of it.

It doesn't matter what you think it says. It doesn't matter what it actually says. It doesn't matter if the entire staff of WotC came and said "this is how it is" and it doesn't matter if a hundred random DMs came and said "this is how we do it". At the end of the day all that matters is what the DM you're playing with thinks - if they want it to have strict concentration, it has it, if they want it "with loopholes", it will be so, if they want it "no concentration needed" then yays all round. It doesn't matter what the book says, only how they want it to work. So any "oh but with THIS word here it actuall means..." out of context nonsense arguing serves absolutely no point at all. It's a nitpicky, trivial and worthless waste of time.

So, the better question is how do you want it to work, and why?

 I actually just want it to work the way it's written. That's the point of this thread. I'm not manipulating the words, I've made a mistake but my point still stands that I don't think concentration ends on a spell when using a feature that has concentration as if it were cast as a spell.

Wording is apparently very important in D&D and sets precedents for what you can and can't do. For instance, a thrown dagger is a ranged attack with a melee weapon but a ranged weapon attack. A bow used to smack someone is a melee attack with a ranged weapon but also a melee weapon attack. But the thrown dagger isn't an attack with an attack with a ranged weapon and the bow isn't an attack with a melee weapon. Another example is that you can't dispel magic magical effects that don't come from spells. Another example is that you can't twin firebolt because you have the ability to target objects. 

It's not like I'm trying to be difficult or whatever. I'm trying to actually get the truth from the wording. I know anyone can rule any way but I'm not looking for anyone's rulings. I'm looking for answers. You've provided what you believed to be the answer but I don't exactly buy your reasoning. 

I'm in neither camp, really. I think the feature is good enough as you interpret it that I'd be fine if the way you interpreted it was how it worked, but I'm looking for something specific that can be applied without being interpreted the way I'm reading it. Something that says "features that end as if you are casting concentration spells also end your concentration." Because the phrase still reads as a parameter for when the feature will end, not when it begins.  

If you are looking for a more official ruling, here is some Crawford Sage Advice on the matter: https://www.sageadvice.eu/2015/04/10/invoke-duplicity/

"If a feature says it requires concentration, as Invoke Duplicity does, you can't concentrate on it and a spell simultaneously"