Do you think there was a significance to Brain saying “They (the BOP and the master’s defender) were meant for you” to Ephemer? It implies that Ava was the one who gave the keyblade to him as well, I really hope this means Ava will have a major active role in the future. It makes the master’s defender parallel no name even more. Now that we know no name was passed down so that MoM could timetravel and write the BOP, I wonder if the Master’s Defender will serve a purpose akin to that for Ava’s plan.
Oh yeah very interesting thought! If Ava indeed gave it to Brain (which, I agree with you that really seems to be the case), it's very interesting that Ava was able to obtain this Keyblade at all to begin with-- especially if it's a Keyblade older than the foretellers' Keyblades. Part of me wonders if the MoM gave Ava this keyblade to her when assigning her role, but was never shown on screen because it would practically confirm that Ava and Brain had a secret second meeting, something hinted at (like you said) but not confirmed.
The reason I wonder if it was when the MoM gave Ava her role is because the MoM implies her role with the Dandelions is involved with the final passage of the Book of Prophecies (IOW the Tear in Time, since it happens immediately after, leading to the Light of the Past scene). And there's a series of points that I have a "conspiracy red string" connecting them all:
Ava's role possibly being responsible for KH3's Light of the Past scene.
Brain ending up in gothic Scala ad Caelum.
Eraqus (who's tied to Brain) knowing about both the Tear in Time and Light of the Past.
the Master Defender being a focus in Ephemer's statue in gothic Scala ad Caelum.
Ephemer appearing during the Light of the Past
DR's tease about Missing Link (spoilers)
So if the Master Defender is tied to all these, we have some mysteries:
Did Ava recieve it from the MoM to pass down to Ephemer?
Why did she keep it until her second meeting with Brain?
If it's older than the foretellers' Keyblades, why did the MoM have it, and what are its origins?
There is a theory its a Keyblade of Darkness, since chip and dale say a Keyblade of Darkness can open the way to the Realm of Darkness, and Sora used the Master Defender to open a door to the RoD. KH3's glossary (The Three Realms) states Sora used the Power of Waking-- which explains why Aqua didn't just let herself out since she had the Master Defender while in the RoD, but the Power of Waking is usually involved with the Station of Awakening (1, 2, 3), so... idk I just am suspicious/open minded for that being the sole reason Sora was able to enter the RoD. But even if it is Keyblade of Darkness, I don't exactly know how that would tie into its role with Ephemer and the Light of the Past.
Either way I just hope to god that Ava comes back in ML. Like, there are SOOO MANNYYYY theories surrounding her, Brain, Ephemer, the Tear in Time/Light of the Past that... if we don't get answers in ML... I really don't know how else Nomura plans to connect all them together...
