I was playing my weekly D&D game this weekend with my friends and we are kinda new.

I ended up fighting my party and was engaged in combat with all 3 of them. The wizard in front of me cast shatter behind me, avoiding damaging his friendly party members and only hitting me.

The DM ruled that it was with advantage because the point of origin was from behind me, even though I had a line of sight on the wizard and was already engaged with him. (We are using a house rule where spellcasters have to roll a d20 for hit for every spell. The advantage was given in this roll.) We were in a normal lit room with no cover between us.

Should he have gotten the advantage on shatter even though I saw him casting it?
What do the game rules say about this situation?
(Alternately, assume we cast a spell that normally had an attack roll, since all spells now have an attack roll under this house rule.)

  • \$\begingroup\$ Comments are not for extended discussion; this conversation has been moved to chat. \$\endgroup\$
    – V2Blast
    Commented Jul 6, 2020 at 7:00

3 Answers 3


The asker mentions he is using a house rule:

after reading your answers and re-read the PHB. We were rolling D20 for hit on every spell then a saving throw(if applicable) on hit.

From that, it's hard to say anything about how this rule works. We have had a DM ruling something along these lines in another question. As I mention there, this is a huge nerf for spellcasters in general. About your question:

There are no (default) rules for advantage for attacking from behind 1

One option we have is an optional flanking rule, which still requires another enemy close to you in order to actually give advantage. You can read more about it here. D&D usually assumes that the character has a 360 degrees field of vision, even if they are facing a specific direction in the grid, for the purposes of being attacked. There are also optional Facing Rules (DMG p. 252), which states

A creature can normally target only creatures in its front or side arcs. It can't see into its rear arc. This means an attacker in the creature's rear arc makes attack rolls against it with advantage.

It is still unclear about an attack from behind coming from a PC that is in the front arc, as it's not a situation that would be usually happening. This is not comparable to casting a spell with an actual attack roll because then the spell would be coming from the same direction as the PC (i.e., front).

So, in general...

Your DM is making a lot of house rules.

Is that a problem? Up to your group. If you, or anyone else, is feeling that these house rules are making the game less fun, unfair or similar, talk to your DM and state your concerns. From my experience, new DMs sometimes make house rules without fully understanding the mechanical consequences of these house rules. Explaining that his modified rules are hurting your fun is usually the best way to make them see it.

You also mentioned your group is new to D&D 5e, while it's not clear if that's true for the DM as well, it is possible that he is not aware that he is using house rules. If that seems a possibility for you, check with him if he knows these rules are not official. Sometimes, simply stating "Hey bro, that's not how it works" is enough for the DM to notice "Whoops, I was thinking about other random system". I myself carried misconceptions from 3.5e to 5e when it was released.

Sadly, as these are house rules, we can't answer, from the rules perspective, more than "none of these rules is stated in the books" and "your DM is the one who makes the rules, so if he said it, he's kinda right" (but he should be consistent - if your spellcasters cast a spell on the enemies' backs, you should get advantage as well). You can make a different question asking whether or not these house rules are balanced and how they impact the game overall, but, as I said, this is a different question.

As a side note, although the Shatter spell is mentioned, the actual problem seems to be about the house rule. Shatter itself could have been a fireball or any other AoE spell.

As a second side note, the Facing also states

A creature can also change its facing as a reaction when any other creature moves.

While "moves" probably means actual movement (walking from a square to another), if the DM is applying the same rule for AoE spells cast in a point of origin behind, he probably should allow you to react and change the direction you are facing to your back, when you see the spellcaster moving his hands and speaking some awkward phrases.

1 Note, however, that a specific rule is not required for Advantage/Disadvantage, as PHB p. 173 states

The DM can also decide that circumstances influence a roll in one direction or the other and grant advantage or impose disadvantage as a result.

This is more a fall-back rule and a reminder that "the DM is in right to rule anything as he wants, to be frank", though, from how I read it.

  • \$\begingroup\$ @IsaacReefman Let us continue this discussion in chat. (This got further than I had expected) \$\endgroup\$
    – HellSaint
    Commented Jun 12, 2018 at 8:34
  • \$\begingroup\$ @SevenSidedDie Added as a footnote with some caveats from my own interpretation. The main body of the question is becoming cramped, so I'm moving things that are not my main point to the end, as side notes. \$\endgroup\$
    – HellSaint
    Commented Jun 12, 2018 at 20:37
  • \$\begingroup\$ Looks good to me! \$\endgroup\$ Commented Jun 12, 2018 at 20:38

This is a case of circumstantial advantage from the rules

The granting of advantage, or disadvantage, can be triggered by either a game mechanic, or by a circumstance-based ruling where the DM assesses the situation and grants advantage. The DM could just as easily have granted advantage for a fire bolt attack as for this shatter spell attack, since both are (per your table's house rule) using an attack roll to see if they hit.

Advantage and Disadvantage

Sometimes an ability check, attack roll, or saving throw is modified by special situations called advantage and disadvantage. Advantage reflects the positive circumstances surrounding a d20 roll, while disadvantage reflects the opposite. (Basic Rules, p. 4 / PHB p. 7)

Applying advantage during play (Chapter 7)

The DM can also decide that circumstances influence a roll in one direction or the other and grant advantage or impose disadvantage as a result. (Basic Rules p. 57, / PHB p. 173)

Your DM did exactly this.

If you disagree with this ruling (I can see why you did) the time to discuss this is after the game. Make your case for why that wasn't a call that made sense to you, and then listen to the response. Then consider what the DM's task is, in making rulings, and make the best of it going forward.

Would I have ruled this way? Probably not, even with the house rule

Unless your table is using the DMG optional rule for facing, I'd not have ruled that the attack had advantage since nothing mechanical activated it. From the DMG's facing rule

... "A creature can normally target only creatures in its front or side arcs. It can’t see into its rear arc. This means an attacker in the creature’s rear arc makes attack rolls against it with advantage." (credit to @Rubiksmoose, page reference later)

On the other hand, your objection based on "I saw him cast the spell" doesn't have a strong anchor to a reason against since shatter (unlike fire bolt or fireball) doesn't describe a telltale visual effect when the spell is cast. You'd have had a stronger case with, for example, fireball.

  1. Fire Bolt: You hurl a mote of fire at a creature or object within range. (BR p. 90)
  2. Fireball: A bright streak flashes from your pointing finger to a point you choose within range and then blossoms with a low roar into an explosion of flame. (BR p. 90)
  3. Shatter: A sudden loud ringing noise, painfully intense, erupts from a point of your choice within range. (BR p. 100)

    While you may have seen the opposing caster cast a spell, you didn't necessarily know what spell it was, nor where shatter was being cast to. There are some optional rules in Xanathar's Guide to Everything that address how to tell what spell is being cast during combat, but I am not sure if you are using that rule or not.

Now what do I (Lemonjuice707) do?

While on the balance I agree with you, it is important for the climate at your table that, before you play again, you discuss this disagreement with your DM and get a sense of "it always works this way" or "in this particular circumstance, I ruled it that way." Understanding that will at least give you more to work from/with. (And where you can, use this to your advantage if you make spell attacks. :) If the DM was applying that aspect of the facing rule, it will be good to know going forward that this optional rule is in play.)


Shatter never gets advantage

Shatter does not have an attack roll. The caster picks a point, and every target in range has to make a constitution save or take full damage. (Half damage on save.)

The DM could rule that you have to make that saving throw with disadvantage because it originates from behind you, which is a weird houserule which I'd definitely not recommend as it will make wizards far stronger than they're supposed to be, but the wizard can never "get advantage" on shatter as they don't have to roll any to-hit rolls.

However, even going by your house-rule of all spells having attack rolls, the wizard still wouldn't have gotten advantage. The closest you get are the optional flanking rules, which only work for melee attacks, or the facing rules which specify the attacker has to be in your rear arc to get advantage, neither of which are the case.


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