Cold. That's how you felt, his throat in his hands. Cold, pale, callous, already. He felt the eyes of his brothers, gasps and horror and pain. He felt Beel's eyes, and for a moment he regretted doing this, he realised he didn't have to, that moment stretched, staying like the stain of blood on cloth. He didn't have to do this.
Instead of confronting these feelings, he wasn't good at that, he looked up rapidly, his hands lurching away from your bruised, still throat. His eyes narrowed, at Lucifer specifically, as if to blame him, to say 'this wouldn't have happened if it weren't for you'. Anything but acknowledge he was wrong, that he shouldn't have done this, like he shouldn't have killed you. With a huff, a grunted one, he stood, angrily, his fists clenched, repeating the actions they easily took around your throat.
"What have you done?" Beel whispered under his breath, followed by a barrage from agreements of the other five brothers. Belphie said nothing, looking down at you again, your body. His face shifted, softening, seeing the stillness of your features, the purple of your lips that used to curve at him from the other side of bars, the paleness of your skin which used to flush in the low, warm light of the attic.
Then, a sound, the sound of three sets of feet at the top of the staircase, three. He looked up, his breath catching in his throat. He met the eyes of Diavolo, Barbatos, and you.