While I wait for the Avengers, here is a little one shot I wrote from Loki's perspective.
I was always cold. Whereas you were the golden child, always the breath of summer, always the one that was wanted, I was ignored- even shunned for my cold demeanour which got more frostbitten over the years. Even my fury was cold, clenching around my heart with an arctic grip.
That was when I would try to best you, try to defeat you. To show myself as worthy of being bestowed with the love and tender soft tones of praise that our (your) father showered on you. My childish competitions and sibling rivalries turned bitter, more violent as we matured, or should I say I matured, you just got bigger muscles. Another thing which I envied you for, and yet I could never understand why people placed such value on them. Could they not see that strength of the mind and cunning had much more practical uses? Off course not, the only example they had of such wit was me- the weakling brother, the one who always had to linger in your shadow.
No more though. No I am seen as something much stronger than your brother. I am your nemesis. I could never have earned any respect while playing the part of the loyal younger brother, so I will earn your respect and your fear as your enemy. And now, unlike before, nothing shall hold me back from defeating you. No brotherly ties, no sympathy for the favourite. I will kill you and when I do, no-one shall underestimate me again. All those who mocked me shall fall trembling at my feet, as I take your place as the beloved ruler of our, and countless others, people.