when casting dragons breath a2nd level spell. It has a 1 minute duration. With concentration. So as I imagine it you cast it on yourself and start breathing damage of said Type. So your character is just standing there spewing (fire) for 10 rounds... if this is the case would you just roll damage once and that’s your damage for all 10 rounds? And the target would roll a saving throw each of there turns? 

The spell says the creature with the Dragon's Breath can use their Action to use the effect. They don't have to. And each Action would be distinct. It would be a new roll for the saving throws and a new roll for the damage.

What if I use glyph of warding with dragons breath inside of it?

It would probably use it's action every round and again it would require a distinct saving throw every round for anyone in it and new damage every round.

Edit:
Corrected by SagaTympana down below.

Okay thank you. You’re probably right.. lol. I was trying to make a broken way of using destructive wraith, with dragons breath.

Quote from tomthompson1982 >>

What if I use glyph of warding with dragons breath inside of it?

As per the text of glyph of warding, dragon’s breath would be cast on whoever triggered the glyph, meaning that the triggering creature would be able to breathe fire (or whatever) on you. Probably not what you’d want, though putting down such a glyph so that you could trigger it later could be a valid and interesting strategy.

Quote from SagaTympana >>

Quote from tomthompson1982 >>

What if I use glyph of warding with dragons breath inside of it?

 

As per the text of glyph of warding, dragon’s breath would be cast on whoever triggered the glyph, meaning that the triggering creature would be able to breathe fire (or whatever) on you. Probably not what you’d want, though putting down such a glyph so that you could trigger it later could be a valid and interesting strategy.

Yea that's true I didn't even think of that. I doubt the Glyph could target itself with the spell and then use the breath.

So what if I cast glyph with the dragons breath spell then had my find familiar walk through it. My familiar would be able to use dragons breath and the glyph would hold the concentration????

Yea - but the problems with that would be:

1. If you move the Glyph more than 10 ft it ends and doesn't go off - so you can't take it with you.
2. Glyph of Warding is a 1 hour cast time spell.
3. Glyph of Warding has a 200g material component.

The possible benefits of using it over just casting the Dragon's Breath on your familiar yourself aren't clear.

What if I cast the glyph on a piece  of paper  tied to my familiar in my bag of holding then had my familiar jump out of the bag but stay within the ten feet?? Because the bag is a different dimension and the dimension doesn’t move would that work?

The moment the paper left the bag of holding it would be further than 10 ft from the place it was initially cast and it would instantly end. Also - your familiar would suffocate if it was in the bag of holding for too long.

And I just want to say thank you to everyone.. This type of back and forth conversation is great. Getting so many different opinions on a subject really gets my creative juices going. 

You can get in the bag to cast it in the bag?

If you’re a gnome wizard you would be under 4ft. Mostly. Lol

Thank you all for your comments.

That’s a great insight thanks it helped a lot.. and sent me thinking in a whole new way.

Could you cast Glyph of Warding into a Ring of Spell Storing?

So then it wouldn't take an hour to cast the Glyph.

It would still take an hour

Casting the spell into bag of holding would not work. If you are too big to fit fully in, you are overloading the bag which causes it to rupture, be destroyed and would send you and anything else in the bag to the Astral Plane. If you are fully in, you can only breathe for 10 mins while the spell takes an hour. There are races like Warforged that don't need to breathe or can hold their breath longer - but they are too big for the bag.

If you want a semi-portable Glyph of Warding you'll need a Portable Hole or the spell Demiplane.

Alternatively, you can get a Ring of Spell Storing and see about fashioning it to your familiar for the familiar to use it. You can then forgo the glyph and just stoe Dragon's Breath into that ring, the familiar can then cast it from the ring and maintain its own concentration. However, the rulings about familiars and items can be tricky - check with your DM.

You can get a Spell Gem magic item. It only requires attunement to put a spell into it, and the spell stays even if you unattune. Attunement is not needed to cast the stored spell. Abjuration spells stored into the gem require only half the normal components - so that's only 100 gp instead of 200 gp. No matter the casting time of the spell, after being stored it requires only 1 action to cast the stored spell. Normally the gem overrides the attack bonus and save DC of a stored spell - but Glyph of Warding doesn't have one for spells put in the Glyph.

Glyph is a touch spell and Familiars can deliver touch spells. So, store the Glyph spell into the gem. When needed, you can use the gem to cast Glyph of Warding as an action, delivered by the Familiar where they are if necessary, and put the Dragon's Breath spell into it with a suitable trigger like when the familiar steps on it. On the Familiar's turn it steps on the glyph, gains the benefits of Dragon's Breath which will use your save DC, and nobody has to worry about maintaining concentration.

You will need a Spell Gem (Bloodstone) or greater. It's a Rare item.

This technique - which is perfectly RAW - is amazeballs when combined with Flock of Familiars. Remote spell traps up to a mile away.