I have a question regarding the Echo Knight. Can you manifest your echo BEHIND an enemy while engaged in combat, effectively surprising the enemy and stopping their next attack? Then when the enemy attacks if you have the sentinel feat, regardless if the enemy attacks you or the echo you have a reaction that you can use from either the echo or yourself to attack the enemy as a reaction?
Sentinel is of use to the Echo Knight primarily in the instance of the Manifest Echo's 3rd ability:
"When a creature that you can see within 5 feet of your echo moves at least 5 feet away from it, you can use your reaction to make an opportunity attack against that creature as if you were in the echo’s space."
Doing this would allow the AoO by YOU from the ECHO's location, at the cost of your reaction, and if it lands, reduce the creature's speed to 0, per Sentinel.
The other two uses of Sentinel are determined from YOUR space, not your echo's. Sentinel will give you the reaction attack if you are within 5 feet of the creature and the creature is attacking your echo (or another target) within its reach.
"When a creature within 5 feet of you makes an attack against a target other than you (and that target doesn’t have this feat), you can use your reaction to make a melee weapon attack against the attacking creature."
If you create the echo behind the creature, you do not automatically create the surprise condition. If the creature attacks you, you do not get to attack the creature from your echo's location. I'd say the surprise condition might come into play if: first, you nor the creature are in combat, second, you are concealed in a manner as to not cause the creature to engage in combat once you draw your weapon, and third, you create the echo behind the creature and you immediately make an attack from your echo's location.
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Sentinel is of use to the Echo Knight primarily in the instance of the Manifest Echo's 3rd ability:
"When a creature that you can see within 5 feet of your echo moves at least 5 feet away from it, you can use your reaction to make an opportunity attack against that creature as if you were in the echo’s space."
Doing this would allow the AoO by YOU from the ECHO's location, at the cost of your reaction, and if it lands, reduce the creature's speed to 0, per Sentinel.
The other two uses of Sentinel are determined from YOUR space, not your echo's. Sentinel will give you the reaction attack if you are within 5 feet of the creature and the creature is attacking your echo (or another target) within its reach.
"When a creature within 5 feet of you makes an attack against a target other than you (and that target doesn’t have this feat), you can use your reaction to make a melee weapon attack against the attacking creature."
If you create the echo behind the creature, you do not automatically create the surprise condition. If the creature attacks you, you do not get to attack the creature from your echo's location. I'd say the surprise condition might come into play if: first, you nor the creature are in combat, second, you are concealed in a manner as to not cause the creature to engage in combat once you draw your weapon, and third, you create the echo behind the creature and you immediately make an attack from your echo's location.