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

[ECMO3]

The enemy doesn't have to move after being hit by an Opportunity Attack according to the Devs
So the sequence would go more as follow. Enemy is sheathed in booming energy to start his turn and right next to me.

Enemies Turn:
1. Enemy attempt moving out of my reach, triggering an AOO
2. Cast Booming Blade via War Caster, hitting it and sheathing it in booming energy
3. Sanctuary drops
4. The enemy either keep moving and take damage from Booming Blade or stay within 5 feet of me and attack me

I think the problem with this is "attempting" to move out of reach does not trigger an AOO. Only actually moving out of reach does.

I can buy that he does not have to complete his move, but he has still moved to the edge of my reach (5 feet), that uses 5 feet of movement and put him in a different location than he started his turn.

If we are to take this logic and apply it to a reach weapon - if an enemy tries to move away when I have a pole arm and I hit him with an AOO from 10 feet away does that mean he never moved at all and is still standing right next to me? To pull this thread a little more, if I do this with Sentinel and he can't move any more after I hit with my polearm, does that mean he can attack me if he has only a 5 foot reach?

 

[ECMO3]

If they leave then they are out of range so the AO can't happen. The only logical conclusion that works with all the other factors, like sentinel and BB , is the movement of space is attempted, the the reaction occurs, then the movement is resolved. That can only happen of the target has agency over where they are.

No. They move to the edge of reach. They have moved before the AOO occurs and if you want to say it interupts it fine, but it interupts the movement at the edge of reach, not where they started the movement.

Like I said in my earlier post, if I have a polearm and I hit you when you leave my 10 foot reach you are not teleported right back next to me. I hit you when you are excactly 10 feet away and you are still 10 feet away when I hit you. Same with a 5 foot reach, you are hit when you are 5 foot away, you are not teleported back next to me.

 

[ECMO3]

In other words they moved 4 ft and the AO happens. They then can continue to move or stay where they are. Nothing in the rules say you must spend movement in set chunks.

I can buy this logic, but the number is 5 feet, not 4 feet. I can hit someone 4 feet, I can hit someone at 4 feet 11 inches, I can hit someone at 4 feet 11 3/4 inches ......... etc. So he is more than 4 feet away.

With a 5-foot reach I can hit someone exactly 5 feet away, I can't hit someone MORE than 5 feet away. So I think he is 5 feet away exactly when the AOO happens, not 4 feet. This is also exactly the movement that triggers booming blade.

 

[Stoutstien]

No. They move to the edge of reach. They have moved before the AOO occurs and if you want to say it interupts it fine, but it interupts the movement at the edge of reach, not where they started the movement.

Like I said in my earlier post, if I have a polearm and I hit you when you leave my 10 foot reach you are not teleported right back next to me. I hit you when you are excactly 10 feet away and you are still 10 feet away when I hit you. Same with a 5 foot reach, you are hit when you are 5 foot away, you are not teleported back next to me.

Exactly. The edge of the reach is something the rules don't play nice with because everything and everything aren't blocks of stuff filling a grid. That's why of you want to use a pole arm to make an AO with the last bullet they must already be ~9-10 ft or you get the issue with hitting something that isn't in reach. They aren't teleporting as much as grids being grids.

 

[ECMO3]

Exactly. The edge of the reach is something the rules don't play nice with because everything and everything aren't blocks of stuff filling a grid. That's why of you want to use a pole arm to make an AO with the last bullet they must already be ~9-10 ft or you get the issue with hitting something that isn't in reach. They aren't teleporting as much as grids being grids.

Well then they are 4-5 feet away in the case I am talking about, not right next to me as others have alluded. They moved 4-5 feet they are in the location they moved to. And I would argue it is 5 exactly, not 4-5 because my reach is 5 feet exactly, not 4-5 feet.

Also if you are using grids and they moved 4-5 feet away from me, they are mostly in the next grid, not in the one they started in.

 

[Stoutstien]

Well then they are 4-5 feet away in the case I am talking about, not right next to me as others have alluded. They moved 4-5 feet they are in the location they moved to. And I would argue it is 5 exactly, not 4-5 because my reach is 5 feet exactly, not 4-5 feet.

If they have moved exactly 5f they are on the line between grid spaces. Which way they finish the last .000000000001 bit of movement is up to them. That one of the reasons grid play is a consider a variant. The assumption is foot by foot so this isn't a problem. Always a trade off when using something to streamline play.

Why I brought up sentinel. Most rule the movement is stopped within the triggering grid because that makes sense but that's inconsistent with the ruling with movement of grid with AOs is unavoidable.

 

[ECMO3]

If they have moved exactly 5f they are on the line between grid spaces. Which way they finish the last .000000000001 bit of movement is up to them. That one of the reasons grid play is a consider a variant. The assumption is foot by foot so this isn't a problem. Always a trade off when using something to streamline play.

Why I brought up sentinel. Most rule the movement is stopped within the triggering grid because that makes sense but that's inconsistent with the ruling with movement of grid with AOs is unavoidable.

Ok I can buy that they can decide which square they are in after the attack, but regardless of which square they are in they still moved 5 feet.

Because they moved 5 feet, they have 5 feet less movement and triggered the original booming blade movement damage (but not the AOO damage if they choose not to move any more regardless of which square they are in) because both of those things happen when you move 5 feet, not when you leave the square.

 

[Maxperson]

If they leave then they are out of range so the AO can't happen.

And if they never leave reach, the AOO never triggers. It can only trigger if the enemy is locked into moving 5 feet away and you then get a swing as it leaves.

The only logical conclusion that works with all the other factors, like sentinel and BB , is the movement of space is attempted, the the reaction occurs, then the movement is resolved. That can only happen of the target has agency over where they are.

Sentinel is different. Specific beats general and it stops you. It isn't evidence that you can just voluntarily stop moving before leaving the 5 feet, which would prevent an AOO from happening.

 

[Stoutstien]

Pettt

Ok I can buy that they can decide which square they are in after the attack, but regardless of which square they are in they still moved 5 feet.

Because they moved 5 feet, they have 5 feet less movement and triggered the original booming blade movement damage (but not the AOO damage if they choose not to move any more regardless of which square they are in) because both of those things happen when you move 5 feet, not when you leave the square.

Pretty much yea. Moving 5ft and moving grid squares can happen together rather than they both must occur in tandem. Going prone or standing up is just a headache though when you are trying to maintain logic and balance with BB.

I just rewrote it so the rider happens like static grounding. so the target can move but if they end up in a space more than 5ft away it triggers. Makes it at least mildly engaging.

 

[Maxperson]

Well then they are 4-5 feet away in the case I am talking about, not right next to me as others have alluded. They moved 4-5 feet they are in the location they moved to. And I would argue it is 5 exactly, not 4-5 because my reach is 5 feet exactly, not 4-5 feet.

Also if you are using grids and they moved 4-5 feet away from me, they are mostly in the next grid, not in the one they started in.

They aren't mostly in the next grid. They are entirely in the next grid. If you want to visualize it as them standing at the edge of that grid that is closest to you, that's fine. In game terms, though, they are out of reach now.