Eren's been betrayed many times before. He remembers how it feels when Mikasa tells his mother that he wants to join the Scouting Legion, or when Hannes tears him away from away from her.
But nothing- nothing could have prepared him for this.
Annie was an ally- even a friend. She taught him how to fight, how to defend himself properly. And in those rare moments, he swears that he saw a glimpse of her smile. But as soon as the happiness appears, it fades immediately.
When he discovers her true form, he can't believe it.
He doesn't want to believe it- not for a single moment. But he remembers what she's done. She killed the ones who had faith in him because he chose to believe in them.
He can hardly register what happens- rage burns through him, anger getting the best of him. It's all a rush- a blur that doesn't slow down.
And the next thing he knows, he's on top of her, fists clenched as he continues to strike her, blood covering their no longer innocent features. But she remains apathetic, lips pursed tightly to suppress any cries.
"I believed in you, Annie!" he yells, voice cracking as tears pour down his cheek. His anger fades into remorse, fatigue setting in. "We all believed in you- and you fucking lied to us."
He wants to kill the female titan.
Not Annie.
A tinge of hope still remains within, desperately hoping that she'll surrender.
But she won't, and she never will.
He has to kill her.
Hands shaking in both fury and anxiety, they wrap around her neck, crimson liquid smearing onto her pale skin.
And he squeezes.
Eren hates it so much- it's a horrible, exhilarating feeling. And that's what scares him.
But Annie has given up, blue eyes staring up at him, tears trailing down her face. She stares into those angry eyes and a feeling of sorrow washes over her.
She's a monster.
She knows.
And he finally lets go as her body goes limp, eyes shutting.
The last thing she sees is her father, waiting for her at home.
The female titan is dead, but Annie remains with him forever.
You can't trust anyone.