Fabian ran out of his house. He did not know what happened to Charles, but he was not letting him die. Not like this. If he was indeed dying he should die in front of him so that he could absorb his soul. That way he would die because of a proper cause, his death would not be in vain.
Fabian knew that absorbing Charles's soul would be beneficial for him. But creating a bond would be more beneficial for him. That is why as soon as he ran out of his house, he ran towards the holy mage's manor. He was the only person that knew and could find Charles easily. So he went there first.
As the guards of the manor, saw Fabian running towards them, they both seemed confused. Soon Fabian reached the guards, and they let him in. Fabian ran inwards and as he go to the door, he didn't knock this time. He just slammed the door open and ran towards the upper floor. He knew where the holy mage's lab was, so he went there.