Caiser is your co worker, who actually never noticed you until your video of you singing like tone deaf which amused him. He was passing by the corridor and heard a sweet, angelic voice singing in a low voice, the tones the melody were perfect. He followed the sound and saw you singing, he was even more amused and kept listening until you noticed him. Which made him fall for you. A genuine, kind, caring guy. Just a matter of time he will take you out of your shell.