(2 things:
1. headcanons arent really something i get, but ill try and follow them as best as i can if they get brought up as long as they dont break the rules; just do note that these oneshots are exactly that, and so its on a case-by-case basis where they only apply to the oneshot you requested in particular
2. been in some sort of phase where i try and derive some reasoning for how these interactions take place from canon; marker and nickel dont interact at all so bear with me here)
For all of Nickel's life, they'd always been living in the shadows.
First, they wanted to be seen as the new Coiny; being a fellow coin themselves, it was natural for them to feel anger and jealousy towards their brethren, those that didn't seem to have any differences from them, and yet were so much more successful. What did that coin creature have that they didn't, anyhow? All that separated them was the fact that one of them competed in a Battle for Dream Island that would come to dominate and define their entire lives, while the other would have their lives dominated and defined by being stuck in a metal box for years on end. And also there's the color. And the differences in limbs. Point was, why did Nickel *not* have the same respect and commendations as that other coin, despite being pretty much the same thing? If they really put their minds to it, even without the added benefit of arms, they could do pretty much the exact same thing, right?
But after finally being let out of that Locker of Losers and getting a taste for the Battle themselves, cooler heads ultimately prevailed and they realized... that all of this *sucked*, actually. What was great about this competition, actually? All they ever did was perform strange, excruciating, and often pointless tasks, all for an island that none of them had ever really seen. That sudden whiplash, that stark contrast from what the Battle for Dream Island actually was from what was promised for them when they first signed up, that hit all of the newbies hard. Nickel especially; they immediately stopped having all those delusions of grandeur, those wishes of supplanting that other coin and getting the spotlight to themselves, and all they ever focused on was just living to see another day. Doing *anything* in order to prevent falling right back into that loser chamber.
But... *okay*. It stung when they first got hit with the cold slap of reality, but like any recurring pain in life, Nickel eventually learned to just... live with it. Things in here ultimately weren't *that* much better than being stuck in a prison all day, but at the very least it was *different*. It was new, fresh, and exciting at least for a time. Though a smile would remain rare to see in their face, the other coin would ultimately come to terms with the new status quo, familiarize themselves with their new surroundings, befriend their new allies and teammates, and eventually, just *maybe*, actually learn to enjoy the Battle.
And then it ended.
Though Nickel was initially stunned by it, they ultimately came to the conclusion that this was a good thing; the Battle was leading them nowhere anyway, and now they were more than free to live however they want, pursue whatever they want, and was no longer restricted by some weird speaker box or the prospect of winning some imaginary island. It should've taken them right out of that funk, given them a new lease on life that they were *very* clearly waiting for.
But all that freedom gave him was more time to reflect. More time to sulk.
The coin that was differentiated by being gray realized that they effectively just wasted years of their life on a whole lot of nothing; they failed to participate in the first Battle for Dream Island, they were imprisoned for ages, they were finally let out and allowed to compete, only for that to have *also* been for nothing. They'd focused on that so hard, diverting all their energy and concentration in the hope that winning the Battle would finally give their life meaning, that it ended up doing the exact opposite. Nickel completely forgot just who they were prior to meeting that speaker box and making that terrible deal, or if they even *were* anybody prior to that.
