This Magician Can Become Stronger by Killing People

The eldest son who traveled through time and became the Earl's family. He thought he could become a member of the family and enjoy status and wealth freely, but he didn't expect to be a prisoner of gangsters as soon as he woke up. Is it an unfortunate coincidence or someone else's conspiracy? In order to seize a chance of survival, he killed an enemy in the melee and finally awakened the information collection system. By killing the enemy, he could obtain part of the deceased's abilities. Counterattack assassins, slay monsters, and watch as he uses the system to continuously acquire abilities from others. He becomes stronger as he fights, and gradually controls his own destiny in this strange and strange world.