It looks like creatures can provide cover but line of sight is blocked by "an object or effect that blocks vision - such as a stone wall, a thick curtain, or a dense cloud of fog." Is a medium creature "an object or effect that blocks line of sight?" It matters to me because cover only affects attack rolls, not spells that require a save other than dex.
If the target has Total Cover then line of sight is blocked and spells that rely on seeing the target are not possible. "A creature" is given as an example of something that provides half cover blocking at least half (but less than 3/4) of something behind it. If you can see any of the target you can cast a spell that requires you to see the target
The rules in the DMG for play on a grid are the following:
"Cover
To determine whether a target has cover against an attack or other effect on a grid, choose a corner of the attacker’s space or the point of origin of an area of effect. Then trace imaginary lines from that corner to every corner of any one square the target occupies. If one or two of those lines are blocked by an obstacle (including another creature), the target has half cover. If three or four of those lines are blocked but the attack can still reach the target (such as when the target is behind an arrow slit), the target has three-quarters cover."
So, medium creatures can provide cover but they don't block line of sight.
Just for reference - here is the line of sight rule you quoted from above. Note that only objects and vision effects are included. Part of the reason for this is that the space occupied by a creature on the map mostly represents the area controlled by the creature and not the actual size of the creature. The creature is also, usually, constantly moving around as part of a combat, so there will be opportunities to see targets on the other side of it.
P.S. Though there are likely exceptions where the DM would give total cover to creatures on the other side - a gelatinous cube that actually fills its space comes to mind as one example.
"Line of Sight
To precisely determine whether there is line of sight between two spaces, pick a corner of one space and trace an imaginary line from that corner to any part of another space. If at least one such line doesn’t pass through or touch an object or effect that blocks vision — such as a stone wall, a thick curtain, or a dense cloud of fog — then there is line of sight."
The way cover is written, if you have a ten foot corridor and a front line with two medium creatures then enemies on the other side of them all have total cover against the rest of the party including second rank. The front line is creatures that block the lines and the corridor walls block the lines along the sides.
The way cover is written, if you have a ten foot corridor and a front line with two medium creatures then enemies on the other side of them all have total cover against the rest of the party including second rank. The front line is creatures that block the lines and the corridor walls block the lines along the sides.
That isn't my interpretation.
"To precisely determine whether there is line of sight between two spaces, pick a corner of one space and trace an imaginary line from that corner to any part of another space. If at least one such line doesn’t pass through or touch an object or effect that blocks vision — such as a stone wall, a thick curtain, or a dense cloud of fog — then there is line of sight."
So you have to decide whether a creature "blocks vision" in the same way that a stone wall, thick curtain or dense cloud of fog does.
"A target with Half Cover has a +2 bonus to AC and Dexterity saving throws. A target has half cover if an obstacle blocks at least half of its body. The obstacle might be a low wall, a large piece of furniture, a narrow tree trunk, or a creature, whether that creature is an enemy or a friend."
This implies that a creature does not block vision as you can still see some of the target behind
"A target with Total Cover can't be targeted directly by an attack or a spell, although some spells can reach such a target by including it in an area of effect. A target has total cover if it is completely concealed by an obstacle."
Total cover means the target can not be targetted directly by a spell, most such spells refer to tagetting a "creature you can see". You can see a creature with half cover but not a creature with full cover.
"If a target is behind multiple sources of Cover, only the most protective degree of cover applies; the degrees aren't added together. For example, if a target is behind a creature that gives half cover and a tree trunk that gives three-quarters cover, the target has three-quarters cover."
RAW cover doesn't stack so if you are in a straight 5ft wide corridor with 8 medium creatures in a line along it whether there is 1 creature or 6 between one creature and its target the target has half cover.
The way cover is written, if you have a ten foot corridor and a front line with two medium creatures then enemies on the other side of them all have total cover against the rest of the party including second rank. The front line is creatures that block the lines and the corridor walls block the lines along the sides.
Both in Sage Advice and RAW Creatures only ever provide half cover so such outcome it would be a DM houseruling.
Target at range caught in melee combat—does that target get some kind of cover or do I get disadvantage? Your target has half-cover if another creature is between you and the target (PH, 196).
The way cover is written, if you have a ten foot corridor and a front line with two medium creatures then enemies on the other side of them all have total cover against the rest of the party including second rank. The front line is creatures that block the lines and the corridor walls block the lines along the sides.
This isn't what the rules say ... from the cover rule I cited above:
" If one or two of those lines are blocked by an obstacle (including another creature), the target has half cover. If three or four of those lines are blocked but the attack can still reach the target (such as when the target is behind an arrow slit), the target has three-quarters cover."
These are lines drawn from a corner of one square to the corners of the target square. If all four of the lines of sight are blocked by creatures then the target has three-quarters cover since attacks can still reach the target because creatures do not (in general) fill the square they occupy. I don't know of a rule saying that creatures provide total cover though a DM could rule that they might in specific circumstances.
Cases like several creatures in a row might be ruled to provide total cover for example but firing between a couple of creatures would likely be only 3/4 cover. The DM could rule 1/2 cover in some circumstances too. I'm not aware of the rule limiting creatures to only providing 1/2 cover - the rule above uses creatures as an example of providing 1/2 cover when 1 or 2 lines of sight pass through their space.
It looks like creatures can provide cover but line of sight is blocked by "an object or effect that blocks vision - such as a stone wall, a thick curtain, or a dense cloud of fog." Is a medium creature "an object or effect that blocks line of sight?" It matters to me because cover only affects attack rolls, not spells that require a save other than dex.
A creature doesn't nornally block line of sight to targets past them.
If the target has Total Cover then line of sight is blocked and spells that rely on seeing the target are not possible. "A creature" is given as an example of something that provides half cover blocking at least half (but less than 3/4) of something behind it. If you can see any of the target you can cast a spell that requires you to see the target
The rules in the DMG for play on a grid are the following:
"Cover
To determine whether a target has cover against an attack or other effect on a grid, choose a corner of the attacker’s space or the point of origin of an area of effect. Then trace imaginary lines from that corner to every corner of any one square the target occupies. If one or two of those lines are blocked by an obstacle (including another creature), the target has half cover. If three or four of those lines are blocked but the attack can still reach the target (such as when the target is behind an arrow slit), the target has three-quarters cover."
So, medium creatures can provide cover but they don't block line of sight.
Just for reference - here is the line of sight rule you quoted from above. Note that only objects and vision effects are included. Part of the reason for this is that the space occupied by a creature on the map mostly represents the area controlled by the creature and not the actual size of the creature. The creature is also, usually, constantly moving around as part of a combat, so there will be opportunities to see targets on the other side of it.
P.S. Though there are likely exceptions where the DM would give total cover to creatures on the other side - a gelatinous cube that actually fills its space comes to mind as one example.
"Line of Sight
To precisely determine whether there is line of sight between two spaces, pick a corner of one space and trace an imaginary line from that corner to any part of another space. If at least one such line doesn’t pass through or touch an object or effect that blocks vision — such as a stone wall, a thick curtain, or a dense cloud of fog — then there is line of sight."
The way cover is written, if you have a ten foot corridor and a front line with two medium creatures then enemies on the other side of them all have total cover against the rest of the party including second rank. The front line is creatures that block the lines and the corridor walls block the lines along the sides.
That isn't my interpretation.
"To precisely determine whether there is line of sight between two spaces, pick a corner of one space and trace an imaginary line from that corner to any part of another space. If at least one such line doesn’t pass through or touch an object or effect that blocks vision — such as a stone wall, a thick curtain, or a dense cloud of fog — then there is line of sight."
So you have to decide whether a creature "blocks vision" in the same way that a stone wall, thick curtain or dense cloud of fog does.
"A target with Half Cover has a +2![]()
bonus to AC and Dexterity saving throws. A target has half cover if an obstacle blocks at least half of its body. The obstacle might be a low wall, a large piece of furniture, a narrow tree trunk, or a creature, whether that creature is an enemy or a friend."
This implies that a creature does not block vision as you can still see some of the target behind
"A target with Total Cover can't be targeted directly by an attack or a spell, although some spells can reach such a target by including it in an area of effect. A target has total cover if it is completely concealed by an obstacle."
Total cover means the target can not be targetted directly by a spell, most such spells refer to tagetting a "creature you can see". You can see a creature with half cover but not a creature with full cover.
"If a target is behind multiple sources of Cover, only the most protective degree of cover applies; the degrees aren't added together. For example, if a target is behind a creature that gives half cover and a tree trunk that gives three-quarters cover, the target has three-quarters cover."
RAW cover doesn't stack so if you are in a straight 5ft wide corridor with 8 medium creatures in a line along it whether there is 1 creature or 6 between one creature and its target the target has half cover.
Both in Sage Advice and RAW Creatures only ever provide half cover so such outcome it would be a DM houseruling.
This isn't what the rules say ... from the cover rule I cited above:
" If one or two of those lines are blocked by an obstacle (including another creature), the target has half cover. If three or four of those lines are blocked but the attack can still reach the target (such as when the target is behind an arrow slit), the target has three-quarters cover."
These are lines drawn from a corner of one square to the corners of the target square. If all four of the lines of sight are blocked by creatures then the target has three-quarters cover since attacks can still reach the target because creatures do not (in general) fill the square they occupy. I don't know of a rule saying that creatures provide total cover though a DM could rule that they might in specific circumstances.
Cases like several creatures in a row might be ruled to provide total cover for example but firing between a couple of creatures would likely be only 3/4 cover. The DM could rule 1/2 cover in some circumstances too. I'm not aware of the rule limiting creatures to only providing 1/2 cover - the rule above uses creatures as an example of providing 1/2 cover when 1 or 2 lines of sight pass through their space.