The Black Knights are unfortunately red. It's pretty vexing - Wizards would never do it in a published set, having a faction with one colour in their name but affiliated with a different colour - but they're freedom fighters, terrorists who only attack (what they see as) the unjust occupying force and only with the aim of liberating their home.

Yeah, that's just unfortunate. I don't think there's any good way round it, the only possible things are:

1. Just accept it.
2. Refer to them by an epithet or nickname used in the series more than as "black knights", or try to avoid refer to the name at all as much as possible
3. Rename them
4. Leave them out (or do less of them)
5. Put them in the wrong colour
6. Drop the whole idea

I think 3-6 are pretty impossible, so the only option is between 1 and 2.

Well, 6 is certainly possible, and indeed a quite plausible outcome of this whole project, but not due to any difficulties with the Black Knights so much as the general issue that finishing a custom set is rather hard :)

But yes, I'm inclined to just accept it as one of the quirks of this set. There probably won't be many places in card text where I need to mention them anyway, so I guess I can do elements of 1 and 2b both.

I think should have said "undesirable" not "impossible", obviously you can make a custom set ignoring the colour pie :) I think you'd basically already decided on the best course of action, but I sometimes find it helpful to explicitly lay out the options and say "this isn't perfect and I'm not claiming it is perfect, but it's definitely better than cancelling the whole thing so I'm going with it for now".

Possible names for a mechanic for the Black Knights:

• Infiltrate
• Sabotage
• Oust, Overturn etc
• Underdog
• Enrage/d
• Guerrilla Warfare
• Rebellion

If anyone has ideas for mechanics with those names (whether or not you know anything about Code Geass), any suggestions would be very welcome!

The flavour of the group is that they're the rebel insurgency. They used to be terrorists trying to express anger with the Britannian Faction, but as the series progresses they become a fully-fledged resistance movement, a rebel army, trying to kick out the oppressors and reclaim their homeland for themselves.

"Infiltrate" sounds like a saboteur mechanic: "Whenever this creature attacks and isn't blocked / deals combat damage to a player, [something]". What are the options for [something], considering this will mainly go on red cards?

• Damage player would be effectively Frenzy Sliver and very boring.
• Damage other creatures, like Skirk Commando, is very good. You get a whole bunch of "must block me" creatures... I guess that works well with the tactics / combat-tricks theme. Can probably only go on one or two commons and one or two uncommons though.
• You get to loot? It's fine mechanically, but the flavour is a bit odd. More suited to spies than freedom fighters.
• What other red common effects make sense as effects to get in the combat damage step? I guess you could add mana, in second main... not very exciting and again somewhat odd flavour.

So far a candidate is looking like keywording Skirk Commando's ability: "Infiltrate 2 (Whenever ~ deals combat damage to a player, it deals 2 damage to target creature that player controls.)"

Your suggested idea for Infiltrate doesn't sound like something that could happen at common, since it's easily repeatable creature removal. I recall an article by Maro saying that Gruul's mechanic changed from being fight-based for a similar reason.
I'll toss out a few ideas based on your names and descriptions:

[Type] Infilration (This creature can't be blocked if your opponent controls a tapped [Type].)
Basically card-type-walk, the main issue here would be lack of interactivity. I changed it to care if the card type was tapped. So we could have "Artifact Infiltration" or Wall Infiltration.

Strike (: Put this card from your hand attacking alongside a blocked creature you control. Return this to your hand at end of combat.)
This is an attempt at summarized reminder wording. Basically the idea is that you get a free hit in with the creature when one of your creatures is blocked. It's a bit like reverse-ninjutsu.

Sabotage— Whenever this deals combat damage to a player, [effect].
Why limit this ability to a keyword, when it can have so many different effects? Have it be an ability word.

Underdog - As long as ~ an opponent controls a creature with a converted mana cost of [~+1] or greater, [benefit]. (Seems especially useful with keywords like Intimidate. Less so with keywords that make the creature better in combat, like First Strike.)

I'm trying to brainstorm for saboteur abilities that don't require commando. Yu-Gi-Oh style traps come to mind, but I don't think anyone wants to see that, exactly. That said, I think traps + morph creates a neat interaction. Something like

Sand Stalker
[no cost]
Morph
Whenever attackers are declared, if a creature is attacking you, you may demorph Sand Stalker.
3/4

Alternatively, to represent Guerilla Warfare, you could just put a lot of Flash in red. I know red doesn't get flash that often outside of Time Spiral block, but I don't see why it couldn't for one set.

How about something like "Tap 3 creatures you control: Deal (some) damage to target player" (or destroy target something?)

Representing terrorists/freedom fighters/guerillas ability to, with preparation, strike in a way almost impossible to defend against, but a complete inability to defend territory themselves.

Link's completely right that my Infiltrate proposal above is utterly unsuited to common.

Strike is pretty interesting, but also somewhat confusing. I think the rules for putting creatures OTB blocking allow the attacker to choose where in the order of blockers the new creature goes. (Or is the creature with strike meant to arrive unblocked? In which case, yowch, makes for painful decisions on the opponent's part if you're attacking with something small.)

jmg is right that morph-style traps actually make a really good fit for this set. It's a bit unfortunate that I'm designing this set while Khans of Tarkir is coming out, bringing morph back after years of absence :) I've done a fair bit of thinking about morph, and the big problem is that morphs are 2/2 creatures, rather reasonably sized, and on many battlefields just adding a few more morphs and keeping them face-down will greatly improve your board position. I haven't come up with a flavour for what that would mean or how that would fit the factions I've got.

Colour-pie-wise it'd be fine for red to get a lot of flash, indeed. I imagine I could give several Black Knights flash for that kind of reason.

V's ability is rather interesting too. Like Link's Infiltration, the problem is lack of interactivity. The set's looking like it'll have a lot of focus on the combat step with many combat-relevant Geasses and combat tricks, plus most mecha only do anything in combat; the direct damage bypasses that, in a way that's flavourful and powerful but rather anti-synergistic.

Strike is meant to be like Ninjutsu in that it puts the striking creature out unblocked. I wish I could think of how to clear up the wording... This sort of does it:

Strike [C] ([C], Control a blocked attacking creature: Put this onto the battlefield tapped and attacking. Return it to your hand at end of combat.)
But I don't think that costs can work like that. Maybe:

Strike [C] ([C], Remove a blocked creature you control from combat: Put this onto the battlefield tapped and attacking. Return it to your hand at end of combat.)

But now it starts to feel a lot less red.

"Put it onto the battlefield tapped, attacking and unblocked" would make it clear. A long time ago I made a card called Infiltration Raid that did something similar.

Not for not, but if the plan is to make it 'not-ninjitsu', wouldn't it be better if... ah... maybe it's better if I spelled out the mechanic:

> Strike (, Return a blocked creature you control to its owners hand. Put this creature on the battlefield, tapped, attacking and blocked by all creatures the returned creature was previously blocked by.)

I know red doesn't want to be blocked... but not blocking is exactly what this mechanic would end up encouraging. With this version, one good Striker in your deck would mean that every block was a liability.

Oh, and we should stop using Strike. What with First Strike and all.

Directly bring back ninjitsu in red, possibly renamed to "infiltrate" or "saboteur"? That seems to fit the undercover revolutionaries, sabotage, slowly becoming an army flavour?

Or, now I read strike in more detail, maybe combine the two, "Unjitsu 3B (3B, return a blocked attacker to your hand: Put ~ OTB from your hand tapped and attacking.)"

If all the personalities are talked about by name.. renaming sounds like a fine solution to me.

Gaining an effect if they get through and deal damage works I guess. Or maybe howsabout if they grow when they get through unblocked? So a small group of not very dangerous seeming rebels that grow in strength as they prove they can succeed? (The obvious downside mirror would probably need to be omitted to get people to play it, though.)

Hmm, the Innistrad vampire ability as on Falkenrath Marauders, Rakish Heir etc. (Before that it was the Slith ability, and before that it was Whirling Dervish... so it's had a fair few flavours over the years.) Yes, that could certainly be flavoured as building a power base or growing in influence. And it's got plenty of precedent in red and green. Nice thought.