the Envy of the most hated creature

In a world of magic and blades, with many races and hybrids between races, there sure are races more loved then others right ?
But in a world where demons hates humans and are hated by mostly all species, what's the worst hybrid to be born to ?
Ding Dong ! A half-human half-demon ! And that's exactly what I am.
And the sugar on the cream ? my born skill can make me grow stronger if I kill demons or humans, so indeed they all thinks I'll use it against humans.
I really envy those who can walk into the streets with great respect and nothing to fear with their great power, I really envy them.
And that envy happened to be what was giving me a chance to reach those I envy.