Hey Mark, just wanted to say that I'm a big fan of graveyard mechanics and seeing Threshold return in Bloomburrow as well as Delirium in Duskmourn has made me really happy. I would like to ask how do you balance using returning mechanics vs creating new ones when designing sets in completely new planes.

If an old mechanic will accomplish what we need, we try to use the old mechanic, but there are a lot of factors that can make us want to use something new instead.

I think Descend X, “if you descended this turn”, and “Fathomless decent”, have a vocabulary issue like Haunt did. They all mean different things. Descend 4 is a condition (similar to delirium/threshold). “If you descended this turn” is an action (similar to “if you milled a permanent or a permanent died” which is “Revolt”). Fathomless descent is neither a condition nor an action; it functions closer to Undergrowth/Chroma as a counting mechanic. As a tiny amount of feedback, using vocabulary in 3 different contexts makes it more difficult to grok (and remember).

Would using three different words for things so mechanically connected not cause more confusion?

Why wasn't "four different mana value" abilities named like Delirium or Threshold?

We have one named mechanic per faction. Having one faction have two named keywords/ability words while others had one would have caused endless letters.

Hi Mark, I hope you're having a good week. What are your thoughts on the card Unholy Heat? I've heard many players say it's too close to a red Doom Blade. And yes, I know there is the Delirium hoop to jump through before you get the 6 damage. But in Eternal formats like Historic and Modern, this happens incidentally. What do you think? Does this card bypass Red struggling against high toughness creatures?

6 is the upper limit for red direct damage. The hoop should matter for some portion of the game, although I get how it might be easier late game.

Delirium is famously one of the hardest mechanics to pull off both in constructed and limited. Did you ever consider making it a scaling ability? (for each card type do X)

No. Limiting yourself to just scaling effects really limits a mechanic.

How directly did Tarmogoyf influence delirium?

Not that much.

Are there silver bordered cards that specifically care about ability words like landfall or delirium? We have, for example, My first tome that looks at flavor text, Duh that looks at reminder text, and many others that look at the full text box, but I can't remember any about ability words. If there aren't, can we get some in Un-4?

Some Un-cards look at all text which includes ability words and reminder text.

I'm surprised that Instant is less likely for a 10 cmc card than enchantment when Instant can have so many ways to reduce its cost. Split cards, delve, convoke, affinity, delirium reduction similar to emrakul, etc all make a 10 cmc instant seem entirely possible in the future while the number of effects an 10 cmc enchantment can have seems very narrow. It feels odd that for this answer "we've never done one" is a reason while for serra angel looking at only whats been done was a negative.

The point of the question is that there is very few 10-cost cards we would do as an instant that wouldn’t just be done as a sorcery. Yes, there’s a narrow band of reactionary spells with a significant cost with a built-in cost reduction, but that is just smaller than the space for a 10-cost enchantment.

So a Reddit thread about cards that are strong in eternal formats but would be fine in Standard got me thinking. Tarmagoyf would have been mechanically very on theme with Delirium and an exciting reprint. Was Tarmagoyf ever considered as a mythic for Shadows over Inistrad?

We talked about it. It was too strong.

It's my birthday! Can I get some trivia on aftermath?

It started as an idea of doing split cards to help Delirium. We then put the graveyard twist on it to play into Amonkhet’s graveyard theme.Happy Birthday!