D&D 5E Using booming blade on a reaction attack with sanctuary question

[Stoutstien]

How are you generating the Bonus Action required to cast Sanctuary?

Huh? There isn't any conflict with using a cantrips and a bonus action leveled spell.

Either way sanctuary is going to break if the BB rider damage triggers and/or you make a OA if you use the updated text.

 

[ECMO3]

How are you generating the Bonus Action required to cast Sanctuary?

I'm not sure what you are asking. I am using my action for booming blade, my bonus action for sanctuary and my reaction (warcaster) for booming blade.

 

[Paul Farquhar]

The only thing I will note though is booming blade movement damage triggers on movement of "5 feet or more" so "exactly 5 feet" is included in this and is enough to trigger booming blade from the original effect.

It's 5 feet from the point of being struck. And at the point of being struck the target is standing on the gridline. Both straddled squares are less than 5 feet away (assuming a 5 foot square grid).

Whilst a mob must end it's turn wholly in a square, it does not have to be wholly in a square whilst it is moving.

Playing without a grid, the reaction takes place at exactly 5 ft. From that point the mob can move any distance less than 5 feet without triggering the booming blade. So they could end up 9.99999 feet from the person making the opportunity attack.

 

[ECMO3]

It's 5 feet from the point of being struck. And at the point of being struck the target is standing on the gridline. Both straddled squares are less than 5 feet away (assuming a 5 foot square grid).

I think you misunderstood what I was saying. I was talking about the movement damage from the original attack (made with an action), not from the reaction attack which is made when "standing on the gridline".

 

[Quartz]

I'm not sure what you are asking. I am using my action for booming blade, my bonus action for sanctuary and my reaction (warcaster) for booming blade.

Yes, but how are you getting the Bonus Action in the first place? You don't automatically get a Bonus Action. Something needs to generate it.

 

[Irlo]

Yes, but how are you getting the Bonus Action in the first place? You don't automatically get a Bonus Action. Something needs to generate it.

No, you can cast spells with the casting time of “bonus action.” Having a spell slot is all the generation you need.

 

[Quartz]

No, you can cast spells with the casting time of “bonus action.” Having a spell slot is all the generation you need.

D'oh! Middle age moment alert!