Marcus is such a tragic character. He's misunderstood and simply stronger than any character I've ever encountered.
He remembers the first day of his pain. He remembers getting to use to it. He remembers it all. He remembers her dainty hands that brushed up and down his bare back, the soft murmurings of her kind words, and the announcement of her death. She was so happy, a trait that is rare in the Volturi; she was full of life. He wanted her back then, but now is used to her absence.
He knew not to wish for something he can never have ever again but couldn't help himself.
He wanted to hold her in his protective embrace and never let her go. He wanted to protect her from the vicious world; wrap her up in a blanket of armour and smother her flawless skin in soft kisses. Her name will forever be branded upon his silent lips. He has lost all hope. He has lost himself. He lost her.
Marcus has never been violent. He has never represented the being he unfortunately is. He's alive but he feels like he has died. All he wants is end it all. End his life. End his misery. And accept the burning flames of hell with open arms. He'll meet his beloved in hell or won't see her at all.
Caius doesn't understand his gentle, dead nature. He doesn't understand losing the one he loved since his stone heart has never loved. Caius has never had sweet sadness thrusted upon him; he hasn't had the opportunity to feel real heart break. Heartbreak: it's a hallow feeling, a real ache in your chest, like a million swords penetrating soft exterior. During heartbreak, you feel helpless, hopeless and tired. A dark room will be your only friend and music will slowly mend your torn chest. And after many months of isolation, you're better again.
But that isn't the case for Marcus. He will never heal. He's broken beyond repair. He's dead. His dead-set face is permanent; the hole in his chest, unfillable; his battered heart forever scarred; his heartache, natural; his hands, empty; his eyes will never shine again.
He will continue to exist but he will never live.
Goodbye, my hopeless lover. Goodbye, my luckless romance.