What van Hoorn lacked in his swordsmithing abilities he made up for in his undermining skills. With a plan in mind, he approached Cleaver and managed to make a deal with his gang to back him up and help monopolize the swordsmithing trade in the city. With the gang at his back, Van Hoorn then began to either buy out his competition by buying their debts and running them out of business, making accusations or, if they were nonhuman, accused them of being havekars, such as the master swordsmith Éibhear Hattori.
To further protect his monopoly, van Hoorn also worked with Cleaver to control all the supplies needed to make swords, hoarding most of them in warehouses and where they sat unused.
If Geralt helps Hattori get back into business: Van Hoorn soon learned that Hattori planned to get around his monopoly and set out to stop him, eventually confronting Geralt and the elf's bodyguard, Sukrus, as they were stealing supplies from one of his warehouses.
- If Geralt runs off: With Geralt suddenly running off, Van Hoorn managed to defend his monopoly with Cleaver's bandits.
- If Geralt fights him: Van Hoorn was summarily defeated and, before he could come to, Sukrus bound him up to be taken to Skellige and where he wouldn't be anymore trouble for Novigrad.