The next morning...
This would be the day Ian activates his core. He decided to do that in the morning. His roomates were out and he wasn't having classes till afternoon. He took out the book and started Studying it. He got to know about the meridians in his body, he got to know about the location of a shadowhunter's core: in the abdominal region. To activate his core, he would have to feel the spiritual energy in the air and breathe it into his body, and direct it to his core. He closed the book and assumed a meditative position and got started. Sensing the spiritual energy in the air was difficult for him, well, other shadowhuters started since they were kids he didn't expect it to be easy. After about 4 and half hours he started sensing something: someone was cooking in the neighbouring room and it smells delicious from the aroma he perceived.
"Sigh". He resumed his concentration. after another hour he finally sensed spiritual energy in the air. As a mundane, there was no way he could describe it at all . His breath quickened but he calmed down quickly. He breathe it in and directed it to his core, this part was easy. The moment his core felt that pinch of spiritual energy, Boundless energy started welling up from within him, his core to say. This energy passed through all his meridians and opened all his pores. "This is the best feeling ever" Ian exclaimed. He could sense spiritual energy better now, all his senses were enhanced. He started absorbing spiritual energy from his surroundings into his core. He stopped when he felt like his core couldn't absorb anymore.
.....
At a desolate place in the city, demonic energy could be seen gathering; at one point. When it couldn't gather anymore, it expanded outwards to form a kind of portal. From this portal emerged a creature Which was curious about where it landed itself. It left this place and started exploring.