Some people who are aware of what Killian's illusions provides are not happy about it and claim the illusions are addicting. They may have a point. Many of those who partake of the Immersion Illusions feel a need to continue to partake of them, almost to the exclusion of anything else. Killian has countered with the fact that the illusions are harmless and only occur within the shop; what people do outside of the shop is not the responsibility of the shop.
Killian DonnerKillian may be an excellent magician but he is an even better drunk; he has a serious drinking problem. This has led to more "legitimate" customers to avoid him due to his either being late or simply doing a sloppy job. He has even lost some of his Immersion Illusions customers; or would have if they didn't feel compelled to get more treatments. With the fact people are willing to pay for the Immersion Illusions even if he can't do them consistently. Killian has found it easy to stay in alcohol; which only makes his condition worse.
Adventure Ideas-The illusions are indeed addictive. That is because the spells Killian uses are all from a codex named, The Amber Light, a book outlawed in most countries due to its highly mind altering spells. The shop and Killian has attracted the attention of some witch hunters who have the book also on their list of proscribed magic. Killian approaches the characters looking to hire them to dissuade the witch hunters from bothering him. Of course, if they take the job they may also have to deal with the arch-lich who is looking for his stolen book.
-Killian has disappeared. Killian owes his landlord a sizable sum and the landlord hires the characters to track him down figuring he'll lose some money but he'll get most of it back from Killian once he is found. He assumes Killian went on a deep bender and is drunk somewhere. However, the story is a bit more dire than a simple drunken fit. One of the shop's customers has kidnapped Killian and is forcing him to continually cast his illusions for the customer. The customer is wealthy and has some political power from old family connections and has no desire to let Killian go as his addiction is too far advanced.