so i realize you're in the middle of star wars or something.
I have come to bargain for that manga yuya declan scene essay with a headcanon!
Since the yuboys are actually different people instead of four quarters of the same guy, the yutrio actually experienced a level of unease/discomfort when commanding the body, especially with mirrors or other reflective surfaces and when they were new to being dead.
But it was important that the yutrio be able to command the body for any stretch of time (see chapter 1 where yuto was in command as a form of disguise), so one of the ways the yuboys use their hijacked solid vision is 'coating' the body in the appearance of the yuboy in command, similar to how action duel fields coat their surroundings, altering yet leaving the original untouched.
Honestly when I read the manga I just assumed that the body's appearance altering was the work of solid vision, the same way Yugo's motorcycle works. I guess that then begs the question: how good is the coat? Are there moments where the illusion slips, where the hologram is imperfect, and snatches of the Yuya underneath sneak through? Because I think that would be cool and also some excellent angst fodder.
Speaking of angst fodder, my long overdue ramblings on my favorite scene from the manga:
One, I cannot stress enough how much I love the decision to make Yuya a stage magician. It fits with him so well I talked at length back when I was reading this that it goes a long way towards giving Yuya more agency than he has in the anime. He literally holds the cards. In this scene he's talking down to Declan, telling him what he's going to do and leaving very little room for opposition. The sense of confidence and self drive that a yugioh protag needs to put there rival in line was just lacking entirely from his original appearance.
But him fiddling with cards as he has a serious talk with Declan is also a bit of more honest and scared emotional communication in this moment, the cards themselves being so integral to who Yuya is that they are basically the other half of the conversation. They're the part he's not saying aloud.
He starts with the Ace of Spades. Commonly referred to as the death card. It's got a fascinating history for why it's called that, but the important part for this discussion is that it's the death card.
So Yuya presents Death, and plays with it. He spins it around on his fingers. He toys with it. Then, in a flourish, he switches it to the joker. I don't think it's a stretch to say he is using the joker as a metaphor for himself.
Then, to demonstrate what he will do to G.O.D, he tears the card, which, if he has not switched it, is still the card representing himself.
And, once again, he swaps it for Death.
To Yuya, the conversation he's having with his magic is this: This is my life's goal. I am willing to do whatever it takes to destroy this card, even dying, because that's the right thing to do. I half-expect, or even fully expect, to die doing this.
That's why I think Yuya looks the way he does in that last panel. He's just laid this all out at Declan's feet. I'd argue this scene is the closest Yuya come to being emotionally vulnerable with anyone in this manga except his brothers. And maybe he wanted a little bit of comfort, or even just a reaction, but just Declan spits out "I still don't consider you a comrade". Oh well. Truly, the one person Yuya bared his thoughts to, the closest thing in this time he has to a living peer who understands him, just refused to even flinch at the idea of Yuya's death. And Yuya wasn't expecting much, but he's still a little disheartened.