A.N. Spoilers ahead!

Verde House

* One of the things that happen in Verde House are that minor plotholes are fixed. For example, I didn't get to show this in-story, but Romeo and Juliet knew each other for less than what, 48 hours in the play before deciding to get hitched? They get a chance to know each other better in Verde House, and they leave when they actually accept each other warts and all, not just the good bits (yes, I know that the play was meant to show the stupidity of youth, but I don't care how much of an idiot you are, you're seriously unlikely to run away and get hitched to someone you literally just met).

* The characters from a particular story don't show up immediately after the story is published, mostly because magic is random and illogical like that.

* The books whose characters have decided to remain in the real world are unchanged - think of the characters there as placeholders. Actors, while the real characters have left the story. I'm botching this explanation, aren't I?

* Verde House is set in the U.S. because that's one of the few places I know reasonably well, and it is entirely plausible that there's a huge mansion and piece of land that's been there since the 1600s, unlike in Singapore, which is just too tiny, or Malaysia and Indonesia, where any huge mansion is highly unlikely to be that old.

* The U.S. Government in-universe knows that Verde House exists, but it's top-secret, and they decide not to step in mostly because they've been doing it perfectly well for centuries, so why bother with the extra manpower and more chance of it getting out? The only part they're really involved in is I.D.s for the characters that decide to stay in the real world.

* The reason it's top secret is that it is just more trouble than its worth if it got out. All you need is a few crazy religious fanatics/crazed moral guardians, some politics, and boom! A mess so huge it actually registers on the Richter scale. Imagine the flak over kids reading Harry Potter. Now imagine if those who protest Harry Potter find out about Verde House and said characters actually coming to life and (sarcasm mode on) encouraging their precious little kiddies to do satanic rituals to become a witch/wizard. (sarcasm mode off) Thus, more trouble than it's worth. Best to keep it quiet.

* The weapons collections consists of weapons from those that chose to stay in the real world, collected over the ages. It ranges from sharpened hairpins to lightsabers, bows and arrows to bazookas, and the odd musical instrument.

* Some of the current generations' ancestors figured out how to charm the wardrobes in each room to have clothes that fit the occupant(s) exactly, mostly because the women got sick of constantly letting out or taking in clothes or in some cases creating new sets entirely. Xavier, Alicia, Julia and Tony are supposed to have charmed a new set, but they never get around to it.

A Picture Paints a Thousand Words

* The gene for magic is present in every child in the family, just that normally it's only in the girls that it's active - the boys are carriers of the gene, but it's dormant unless something happens to activate it. Mind that I'm still in school, so my understanding of genetics is flawed.

* If you haven't guessed, grabbing onto an Artist while he/she is doing the spell drags you along for the ride, and the more people to bring across universes, the larger the strain on the Artist.

* The spell is made to exist only in the real world so that those from other worlds can't get hold of it and abuse it.

* Drawing a living being means that you're really just summoning it from whichever universe it's from, not creating one from scratch. The pony Lucy drew happened to match one from the Crusades exactly, for example, and it got summoned to the twenty-first century.

Two Worlds Collide

* The reason Christina felt 'itchy' when she was handling the sabre she created for Xavier was because she created an exact replica of what he normally used, including the same magic used to make it repellent to all magic but the one used to make it repellent - why Xavier could handle it without any trouble. The weapons used by the guards were made using wizarding magic, so both of them were affected. 

Magic in general

* There are different types of magic, each different and more suited to a particular use, but are similar enough that it can be adapted for another use. So an Artist could cast spells normally done with wizarding magic, but not well. No type of magic is weaker than the other, just different.