If an Echo Knight fighter turns invisible, do their echoes also turn invisible?

Question

My question is inspired by this question: How can I make an Echo (or any Object) invisible?
I was about to answer it by saying that the invisibility spell would work. However, on second thought, it's not clear to me that that's actually the case.

The description of the Echo Knight fighter's Manifest Echo feature reads, in part (EGtW, p. 183):

This echo is a magical, translucent, gray image of you [...]

If the Echo Knight turns invisible, do the images also become invisible (because they are images of the invisible echo knight)? Or do they continue to appear as translucent gray images of what the knight normally looks like when they are not invisible?

Answer 1

The Echo Knight fighter's Manifest Echo feature description says (EGtW, p. 183):

Your echo has AC 14 + your proficiency bonus, 1 hit point, and immunity to all conditions.

And strangely, "invisible" is a condition.

This suggests to me that your echo is immune to being invisible.

Your DM might be willing to fix this with a house rule, but at that point we're in "ask your DM" territory.

Answer 2

The description for the Echo Knight lacks any prescription for effects on the player having "mirrored" effects on the echo. Therefore we can confidently state that the echo does not become invisible. Dan B also correctly points out that the echo is immune to the invisible condition.

However, it should be noted that, while the Echo Knight is invisible, the echo's attacks have advantage. This is because of the following part of the Manifest Echo feature description (EGtW, p. 183):

When you take the Attack action on your turn, any attack you make with that action can originate from your space or the echo's space. You make this choice for each attack.

The Echo Knight is the one making the attacks from the echo's space; therefore, their attacks have advantage, as stated in the definition for the "Invisible" condition:

Attack rolls against the creature have disadvantage, and the creature’s attack rolls have advantage.

Interestingly, attacks against the echo itself do not have disadvantage, because the echo itself is not invisible.