Viggo's master plan (and evidence proofing it or going against it)
Proof of Viggoâs âfake warâ:
Viggo somehow knows where Ryker would strike next
When the Shellfire attacks Caldera Cay, Viggo escapes. And then Ryker surrenders in Outcast Island, as if he knew that they would go there, while the Shellfire attacks at a different island (Viggo might even be switched control over the Shellfire during that time, but that wonât add any proof).
Viggo conveniently appears to Hiccup after the Shellfire attacks Beserker Island.
We never saw Ryker commenting about killing/destroying his brother during his attack at the Edge
Viggoâs chuckle in the end (Y'know, he couldâve just remembered a funny joke and laughed about it, but Iâll add it anyway xD).
Proofs/ thoughts that are against Viggoâs âfake warâ:
If Viggo would want to damage the riders, he couldâve just relocated his base and plan an ambush with Project Shellfire while providing them no solution and keeping the Dragon Eye safe.
It doesnât make sense for Viggo to risk so much resources just for this mission. Ryker and the army was probably prepared to be lost. But logically, risking a battlestation as a mere tool to be lost is too wasteful, even for Viggo.
Why would Viggo unleash a Submaripper to deal with the Shellfire? (I will try to rationalize this below)
So, if we were to consider the betrayal plot was a conspiracy, what exactly what Viggoâs masterplan? In my opinion, it might be to get close enough to defeat the riders from the inside and to destroy the Edge. Though his methods using the Dragon Eye is beyond me (unless he just wants to toy with Hiccup, promising him victory but then leaving him biting the dust)
My Theory on His âFake Warâ Plan
So, the first step of Viggoâs plan would be to attempting to win the ridersâ sympathy by helping them predict Rykerâs next attack (which is suspiciously correct) and promising them information. During the attack in Caldera Cay, he took the time to escape. While it is not seen on screen, it is most likely that he rejoined his army and predicted that riders will attack Outcast Island (because he is Viggo lol), before commanding that Ryker should make them more confused by surrendering and presenting the other side of the story. He also orchestrated the attack in Beserker Island (he might even be in the Shellfire ship), before approaching Hiccup with the Eye, to further make him believe with his story. It is indeed a risky move, but like what weâve seen previously, he would be willing to manuever in risky waters for ultimate victory. Even if he ends being imprisoned, Viggo is sure that they wonât stand a chance with the Shellfire unless they enlist his help (But Snotlout made it much more easier by nearly killing him lol). He then summons the Submaripper as a part of his own personal plan which Ryker and the rest doesnât know about.
About him awakening Submaripper, yeah thatâs very questionable. At first, I thought he might had actually planned to kill/ blackmail Hiccup, using the presence of the Submaripper to escape blame if someone was to catch him during the act. If he was able to kill Hiccup during that moment, his game wouldâve ended there, with the riderâs âviking chiefâ dead. But I doubt he would even try that, especially above a Night Fury and a Submaripper. Heâd be dead after his nemesisâ is killed.
So, I think he did it to either:
to distract the Shellfire, so he could have enough time to get the Dragon Eye back and escape
To make his cooperation convincing to the riders (which I highly doubt due to the losses in stake).
Ultimately, the Submaripper allowed Viggo to be dropped by Hiccup, due to him âslowing them downâ. While this action could have contradicted his plans to sink the Island, I think Viggo perfectly knew that the Shellfire wouldâve suceeded in activating the volcano anyway, given the damage done to it at the last attack by the Eruptodon. He probably didnât expect the baby Eruptodon, but it made little difference anyway. However, the baby dragon did not only help the riders, it was also inadvertedly working in Viggoâs favor instead, stalling enough time to retrieve the Eye.
From what I remember, Viggo also didnât know where the riders were keeping the Eye after Snotlout imprisoned him in the burning stable, so I think after getting dropped off, he probably decided to search for the Eye in the base, before planning an escape. Turns out, he doesnât find it, and Astrid unexpectedly found him out (again). He probably managed to best her âsomehowâ (wth Astrid, you could have kicked his ass). While he knew the gang would be willing to risk their own life for duty, he also knew that they could only be blackmailed by threatening their team-mates instead. Especially Hiccup (who most definitely knows where the Eye is compared to the others. Not to mention the Viggoâs delight of seeing his archnemesis admitting his victory) in the case of Astrid. So he forced Stormfly to fly after Hiccup to the volcano. If his plan was to be successful, maybe Viggo would even consider to kill Astrid as unlike the Buffalord, he has no use of Astrid. Plus, Astridâs death would cripple Hiccup and the gang further more, because losing the Eye and their base is just not enough.
The one thing he didnât expect, is Hiccup throwing the Eye to the volcano (from the look of his face, he is genuinely surprised. But I could be wrong). This small detail destroyed his plans and left him with nothing. Eventually, even his life is lost (If he did indeed die)
But this theory might not be true considering the proofs against this theory, I could also be possible that things went out more similar to what had happened in Viggoâs story.
Like Viggoâs explanation, Ryker manages sway the hunters to betray Viggo and destroy the riders themselves with the power they gained through Project Shellfire. Viggo could have eavesdropped on their conversation, so he knows Rykerâs next move.
Seekng the opportunity to escape when Caldera Cay is attacked, he went to find the Dragon Eye (and some new clothes) and give it to Hiccup, deciding to work together for him until the time has come for him to take back the Eye.
If this was the case, summoning the Submaripper makes more sense. Viggo would never be able to take over the weapon anymore, so he might as well destroy it along with his brother.
When the Shellfire leaves the battle, Viggo takes the chance to find the Eye, probably by searching for it in the base (because again, he didnât know where the Eye was). Astrid discovers his actions and probably tries to stop him, only to be defeated. He then goes after Hiccup, for his sweet victory. Still, there is a possibility that he would betray his promise kill Astrid anyway, that is until Hiccup throws the Eye to the volcano.
So, in the creative point of view, I prefer the first one, but the second one is the most logical IMO xD.