This is a "Wild Mass Guess" entry, where we pull out all the sanity stops on theorizing. The regular entry on this topic is elsewhere. Please see this programme note.
Seven Little Killers
Theories on the remaining killers
Who I think the rest of the killers could be:
Yellow is England
Reasons being his constant use the the word "love," him saying "Whatever I can't see isn't there," and how he was talking to Alaska before killing him. Also his psychological way of tormenting China is something England can possibly pull off.
confirmed as of Chapter 43
Red is Hong Kong
Red seems very quiet, serious, and mysterious, much like Hong Kong
There was one line during the scene where the killers chase Iceland that said the eyes behind Red's mask were brown. Most of the Asian nations have brown eyes and he's currently the only Asian left capable.
The authors uploaded thesetwo somewhat spoilerific pictures on DA involving an insane Japan, Taiwan in a cage(?) and a beaten up (by insane Japan) Hong Kong. Interpret for yourself if this is any further proof of Hong Kong being Red, or at least one of the killers. WARNING: The pics are Rated M, like the fic, so if you don't have a DA account with the Mature Content Filter OFF you can't see it.
Red has a quirk where he tilts/cocks his head like "the way a predatory bird looks at its prey before pecking." Looks closely at the chapters with Hong Kong in them, especially the earlier ones, he has this quirk too.
Pink is Liechtenstein
As of recent chapters, Pink has been described to have been shy and nice at first, but now cracked. Pink is also a girl who got really jealous of Belgium and Netherlands brother-sister relationship. Switzerland was the first to die, so Liech snapped after recovering from depression, unless she was faking THAT. If you look at how she acts on the phone in the first chapter, one could theorize she was distracting Switzerland.
However the Eye Opening Chapters stated that Pink was in the meeting when they decided to kill Switzerland. In the meeting Pink suggests that they kill Liechtenstein and made no defense for not killing Switzerland when it is brought up.
She could just have been protecting her identity? Remember pink was the last to reveal his/her identity. And I think its just now that the authors started using feminine pronouns for her. If not a good second guess could be Latvia for the same reasons minus the distracting Switzerland one.
This troper always thought Pink was Latvia simply because Yellow has a throwaway line about her smelling like "dog poop and broken dreams". Who took home China's less-than-potty-trained Kitty?
Alternatively, Pink is Seychelles.
Pink has the spirited, flighty, slightly flirty personality this troper associates with Seychelles, and in the scene where Pink tortures the Benelux sibs she is shown to be jealous of comradeship - something I don't think Seychelles, being an island colony, had much of. And don't forget that during Romano's killing, France (this WMG assumes that France is Purple) was to visit him that day but left to care for a sick Seychelles...
Or...Pink is Belarus. The reasoning is that Pink has been described as being bi-polar, insanely jealous of sibling love and having a thing for knives.
Or Poland... C'mon I can't be the only one who immediately thought pink—> Poland?
Purple is France
Not much proof other than his relationship with Yellow and their conversation about London being targeted. Second guess would be Prussia.
Also, when Vietnam is being killed, Purple breaks rank and Yellow has to hold him back. There were multiple times where France is stated to have had relations with her.
As of Chapter 43, and England being revealed as Yellow, this is looking more plausible.
And when Romano was killed, he was supposed to be meeting France... Only to have him call and cancel at the last minute, while White was there about to kill him.
White is Austria
Not much proof other than he wants to raise an empire with Hungary and this would be the best way to do it.
When White killed Romano Austria was with Hungary, Germany, Italy, Japan and Prussia, so it's unlikely that he is White. Unlikely, but in this story it could be possible...
Green is Lithuania.
Close to Blue/ America, supposedly close to Black, wanted to kill Russia right away, confesses it in Chapter 17. Now, possibly faking death
I refuse to believe that he really is dead. Just the wording used about his "corpse" makes it seem like it could be a very very realistic fake to me. It is a mind screw they have yet to pull off.
And if I may add a more legit reason to why I don't think that, in order to kill the countries, you have to destroy their capital city. So far, whenever someone's capital was destroyed, it was either mentioned by others offhand (ex: Finland and Helsinki) or happened "on screen" with the nation feeling the effects. (ex: Switzerland and Bern, England and London, etc) Correct me if I'm wrong, but the only ones who died without mention of their capital being destroyed are Korea, Greece, and Cuba who died by getting crushed, falling into a meat grinder and getting chopped up respectively, something there is no way they can be revived from. Currently, for all we know, Vilnius is fine and Lithuania is just knocked out, or a fake corpse. Or he can possibly pull a Russia.
It would be very easy to fake his corpse since he was 'killed' by having his head was smashed in. All you'd need is some poor guy with a similar build, dress him in his clothes and voila! As long as noone activly sets out to identify the body, then you have a perfect fake.
Black is Poland
Wants to kill the world so a new peaceful one will rise from the ashes, happened to be in Russia with Lithuania when Russia was attacked, Lithuania said he "hasn't killed anyone" and technically Black hasn't killed anyone himself.
I didn't think that any of the killers knew Black's identity?
This Troper's headcannon is that Black is HRE.
I like to think Black is Italy. His killing seems to come from a place of weakness - kill off the big three - and his motive to make the world a kinder, better place sounds a lot like something our dear Italian would say, doesn't it? Besides, what better way to make sure that your killers are doing a good job, than to be on the team looking for them.
This Troper says Black is Sealand.
This Troper agrees! After all, Finland calls Black a "baby" and claims to know him very well...
Orange is Ukraine
Already confirmed in chapters 40/41, unless the authors really want to MindScrew us.
Blue is American AND Canada
Confirmed to the sky and back
The identity of 21.
I can't be the only one who remembers this guy and is trying to figure out who he can be. My guess goes to either one of the remaining Nordics, or Estonia. No reason in particular as 21 doesn't have many clues leading to him, so just some guessing.
21 Is a killer...
One of the killers wants to warn their loved ones, but still seem loyal to Black. I think it's Green or White. (Green is the most sympathetic, and White would be an epic twist.)
Instead of one of the lower killers being 21, 21 is actually Black manipulating everyone. This would boost his status as The Chessmaster to sky-high levels.
Why 21 hasn't been showing up recently...
...Is because he died sometime after his few appearences. List of people who died in that gap please?
Everyone who's died since 21 last appeared (spoilers unmarked):
Any of those sounding good?
21 is Black
Reason for this is because of the blatant references to Higurashi. Since in Higurashi, 34 who was "helping" them in the first arcs is Takano Miyo, who ended up being revealed as the Big Bad, this is actually plausible. Also, in a related topic, can you think of a Nation whose human name could be written using numbers?