What methods are there to cause a Blinded (but not Deafened) creature to lose track of my position?

Question

The scenario.

I'm playing a level 3 Sorcerer, using the Shadow Sorcer Origin provided by Xanathar's Guide to Everything. Before combat began (or in the immediately previous round, if you like) I cast Darkness, using my Eyes of Darkness feature on a dagger that I'm holding in my hand. I hold a Rapier in my other hand. Because Eyes of Darkness allows me, the caster, to ignore the effects of my own Darkness spell, I am perfectly capable of seeing through my own darkness but my enemies cannot see me. If they become blinded (per the Condition).

This round, I run up to my target, a Human Bandit, using 15 feet of movement. I drop the dagger on the ground, and then use the Rapier (the character is Drow, so they have Rapier proficiency) to attack the bandit. Regardless of whether the attack connects, I then use my remaining 15 feet of movement to move to another point within the 15 feet radius sphere of Darkness ... I left the Dagger where I dropped it. This movement does not trigger an Opportunity Attack, because an OA requires the person making the Reaction to be able to see their target, which they can't in this scenario.

So here's the core question:

1. Does the Bandit know where I am, beyond the obvious knowledge that I'm still somewhere inside the sphere of Darkness?

2. Does this sequence of events require me to use the Hide action to conceal my new location, or would the Bandit implicitly know my new location, through implied noise that my movement creates?

3. Is the Bandit's knowledge of my new location contingent on their own Perception check against my Stealth abilities, or would they be able to know my position without any checks at all?

   In the Player's Handbook, in the section for "Making an Attack", there is the following information (relevant parts emphasized by me):

   Unseen Attackers and Targets

   Combatants often try to escape their foes' notice by hiding, casting the invisibility spell, or lurking in darkness.

   When you attack a target that you can't see, you have disadvantage on the attack roll. This is true whether you're guessing the target's location or you're targeting a creature you can hear but not see. If the target isn't in the location you targeted, you automatically miss, but the DM typically just says that the attack missed, not whether you guessed the target's location correctly.

   When a creature can't see you, you have advantage on attack rolls against it.

   If you are hidden—both unseen and unheard—when you make an attack, you give away your location when the attack hits or misses.

   My takeaway from this is that simply being in Darkness is enough to fully conceal my position, but that attacking is enough to give away my location. Does this imply that even if I move 15 feet away afterwards, that I've made too much noise this round to fully obscure my position, or is the bandit only informed that I was in melee range in front of them at some point during the round?

Answer 1

You must take the Hide action to conceal your location

In combat, Hiding is never an automatic thing (unless some feature specifically says it allows you to). It always requires you to take the Hide Action.¹

Even if you cannot be seen, you can still be heard and hearing is enough for an opponent to discover your location.

The rules for Hiding state:

You can't hide from a creature that can see you, and if you make noise [...] you give away your position. (PHB 177)

Being in darkness in not enough to conceal your location. Concealing your location has a certain mechanic to it and that mechanic is called the Hide action.

Jeremy Crawford agrees here:

Q: My PC uses the invisibility spell, does he auto hide or do I still need to take the hide action to not be targeted?

A: The invisibility spell doesn't automatically hide you; you still make noise.

Invisibility here functions mechanically identically to your darkness for the purpose of the discussion of hiding in that it makes you unseen relative to the enemy. And neither will allow you to hide without taking the Hide action.

If you don't Hide, your location is known

So, if you are moving around an enemy and you don't take the Hide Action then you are heard and your location is known. In this case, they will be able to attack you (at disadvantage) in accordance with the rules on attacking unseen enemies.

When you attack a target that you can't see, you have disadvantage on the attack roll. This is true whether you're guessing the target's location or you're targeting a creature you can hear but not see. (PHB 192)

The enemy doesn't need to make a check (perception) and neither do you (stealth). Since you aren't trying to hide your whereabouts using the Hide action, they simply know where you are by hearing you.

Hide to conceal your location

However, if you take the Hide action you once again follow the rules for Hiding:

When you try to hide, make a Dexterity (Stealth) check. Until you are discovered or you stop hiding, that check's total is contested by the Wisdom (Perception) check of any creature that actively searches for signs of your presence. (PHB 177)

If you succeed and keep succeeding at that check, you are now "unseen and unheard" and your location is unknown. The enemy must guess your location in order to attack you. This falls under the rules for Unseen Attackers and Targets:

If the target isn't in the location you targeted, you automatically miss, but the DM typically just says that the attack missed, not whether you guessed the target's location correctly.

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^{1 - An argument could be made that, outside of combat, taking the Hide action explicitly might not be necessary to be hidden, but this is outside the scope of this Q&A.}

Answer 2

Take the Hide action.

The Unseen Attackers and Targets rule says:

When you attack a target that you can't see, you have disadvantage on the attack roll. This is true whether you're guessing the target's location or you're targeting a creature you can hear but not see.

This implies that without seeing you, they can still track you by hearing your movement. It's accurate enough that they can attack you with disadvantage.

(It's not clear how far away they can detect you. This would require a ruling if you went very far away but as a rule of thumb, I'd suggest it should work at least within one turn's movement distance. If they want to do something like Fireball your position as you're running away then it's going to be a lot harder.)

Since they can't see you, you don't need to go anywhere to hide; you just stand still for a few seconds, or make some noise somewhere else (for example by tossing a small object away from you), to confuse them about where you are. You have to make a Stealth vs. Perception check to succeed, but they have disadvantage on Perception because they can't see.

If you beat their Perception then they can still try to attack but they are now "guessing the target's location", which is going to be pretty random. For example they could strike at wherever they last saw you, or in a random direction. I don't think there are any rules for how to adjudicate this but the important thing is that they can't perceive you with any of their senses.