Hey Mark, first time asking for Birthday Trivia. Saheeli is my favorite walker so maybe something about her or Kaladesh, or Thopters, something Saheeli-adjacent is cool too. Thank you for being awesome and have a great day.

Originally, Chandra was going to be the face of Kaladesh, but we realized she made more sense for Aether Revolt, so we designed a new planeswalker. We wanted to play up the invention theme, so we made a character that was an amazing inventor, Saheeli.Happy Birthday!

Today it was previewed that the Rebel creature type is returning, this time detached from the Masques block tutoring mechanic. Now that it's no longer a special mechanic-restricted type, will it be added to other creatures that are clearly rebels (for example, Frontline Rebel from Aether Revolt)?

There are no current plans to do that as far as I know.

While I understand the complexities that prevented the artificers in Aether Revolt from having the creature type Rebels, doesn’t Frontline Rebel violate the “card names with a class name should have that class” guideline? How do you balance this, especially looking at the possibilities for reprinting such a card where the nuance of why it’s not a rebel may be lost?

I think it should have been a Rebel. That said, monitoring creature types can get pretty complex. They are the one part of the card that regularly has mechanical and creative ramifications.

In the mechanical color pie article it still lists white as being primary in enchantress effects, but white hasn't received a full enchantress effect since Planar Chaos (Mesa Enchantress) and hasn't received an aura specific enchantress effect since Aether Revolt. (Sram) Why is it still listed as being primary even if it almost never receives this effect?

Being in color pie means it’s available to get it (with a restriction of one card per turn).

For my 29th bday I wish to invoke the rite of bday trivia, and about Kaladesh/Aether Revolt development. Anything fun, cute, or quirky about that time?

Ian Duke who co-led Kaladesh development made an elaborate chart of what effects you could get for each amount of energy. He and his team spent a lot of time on the energy economy.Happy Birthday!

Mark, when I was still a kid, I begged my parents to let me go to the aether revolt prereleases because it was the "coolest set they've done in awhile". But. Then I kept saying that for every set that. Followed

We’ll try to keep that up.

What was the newest-released set when R&D began work on Theros: Beyond Death?

We start design in sets about three years prior to release. So, around the time Aether Revolt came out.

What was the newest Standard set at the time that it was determined that WAR was going to be the Planeswalker set?

I handed off the design two years ago. So, you all were playing Kaladesh and Aether Revolt while vision design was working on it.

How soon before a set releases can you still change cards? If you had found out about the Felidar Guardian combo a month before Aether Revolt was set to release, could you have changed it in time?

The earliest set we could do a last minute fix on if today we realized there was a problem would be Archery (the October set).

While sorting my cards, I discovered that there were some cards that on older printings, used the conjoined "AE" in a lot of Aether cards, but nowadays they are printed as two distinct letters. Why the change? Even Gatherer recognizes and uses the old lettering.

The Ae ligature caused all sorts of problems both internally and on social media when people were trying to reference the cards, so with Aether Revolt, we reverted it to an A and an e.