A little psychoanalysis on Alvin the treacherous.
So I was bored at work and thinking about what could lead a man to be as vile as Alvin. Of course, he might have always been this way. Maybe he was a cruel and vicious person since he was a child, but the httyd books seem to like doing parallels a lot, so I wondered, what if Alvin was a boy a lot like Hiccup when he was very, very young? Smallish, soft, kind, and polite.
I think that would have gotten beaten out of him by living with the Outcasts, his horrible mother, and possibly the Outcast version of the Pirate Training Program.
From what it seems, every tribe has a version of the Pirate Training Program to train their youth. The Outcast Tribe is so violent and sadistic that its people were outcast from normal Viking society—a society where murder is justifiable, stealing is good fun, and slavery is simply a part of life. That gives you an idea of just how brutal the Outcast Tribe is. If you've been outcast by your tribe, you've pretty much already proven yourself. However, if you were born into the tribe, you would still need to prove yourself, as they don't seem like the kind of people to go easy on anyone.
I really can't theorize on what the Outcast initiation or training might look like, but the sky's the limit. Whatever dead-dove-do-not-eat, dark, grim, bloody scenario you can think of, I really wouldn't put anything past these people. All-out war. Maybe Alvin had friends who were kinder and weaker than the others, and he had to watch them get torn to absolute pieces. Maybe he even had to torture or kill them himself as part of the initiation into the tribe. Maybe cannibalism was involved. Why not? They already do it.
Then, in order to cope with what he's done, he adopts the persona of Alvin the Treacherous. Sometimes it can feel easier to just be a "bad person" rather than a person who did a bad thing, because then you have someone else to blame. It's not HIS fault he does what he does--he's evil; destiny made him evil; the Treacherous blood made him evil.
The more he sinks into this mustache-twirling, conniving villain, the easier all the hurt becomes to swallow. After years of pretending not to care, pretending to like violence to keep himself sane, eventually he starts to not care and enjoy it for real.
This could be part of the reason he hates Hiccup so much. Firstly, Hiccup would remind Alvin of a part of his past he tried to bury. Secondly, when they first meet, Alvin might be jealous of Hiccup's life, the life he desperatly wanted but never had. Sure, Hiccup gets bullied, but he has friends who aren't dead, a family who genuinely loves him, and a teacher who's--to a degree--actually concerned about his survival.
His hatred of Hiccup would only grow the more hardships Hiccup faces because, whereas Alvin's trials made him cruel, Hiccup only seemed to become kinder and more selfless as a result. Hiccup keeps winning without having to become monstrous, forcing Alvin to consider that maybe it didn't HAVE to be the way it was. Maybe it COULD have been better. Maybe he COULD have been better.
None of this excuses Alvin's actions, but it did give me some interesting perspective. As much as I do love Alvin being a simple, theatrical cartoon villain, it's fun, it is still interesting to consider alternative angles. The worst people in the world are still people, and I think that's the tragedy.