What’s Ruler?

Digimon Battles (DMB) set Data Breakers brings with it a new category of Digimon—Ruler. Much like Jungle () or Nightmare (), it obeys the rules of evolution. However, there are many rules it does not obey and -Digimon have a lot of special features you should know about, as well as design philosophies that you will notice as trends among their cards. Let’s get started with a list of what they can and can’t do:

Rulers can gain any number of types (or lose them) once per turn, on their owner’s turn before attacks are chosen. This is called the “Dominion” ability. Treat this as “[1/Turn] Any Own Prep or Evolve Phase“.
Rulers can gain (as per the above) only types printed in the Active Zone stack. Examples below.
Rulers can evolve normally using DP or DNA where appropriate. They must follow normal rules. Example below.

Non-Rulers can’t gain this as if it were a type. Cards will be printed with it instead.
“Ruler” cannot be referenced by effects that target “type”. Meaning evolve effects that “ignore type” can’t ignore Ruler. Ruler must be specified by the effect, rather than as a part of the 8 Digimon Types.
Rulers can’t lose this, as though it were a type, ever.
Rulers can’t truly change the property like types. Similar to the above, however they will gain types when a “change” attempt is made. If a subsequent “change” occurs, the previous type does change. Examples below.
Nothing can evolve into a Ruler via DP or other normal means of evolution unless it is also a Ruler OR has the name present in its evo-box. Otherwise, it must specifically “ignore Ruler” to bypass this.

It’s better to think of Ruler as a property than a complete type. Or to think of it as a partial type with many exceptions. Okay, generalities are fine and all but what about specific examples? Here’s two of the cards from Data Breakers:

Examples of Use

In the example, there Magnamon and Alphamon. All we need to worry about for now are names, evo-boxes, and type. Here are some examples of what does and does not apply to them:

Magnamon can evolve into Alphamon via DP because they are both Ruler. Even if Alphamon did not have “Magnamon” in its evo-box.
Knightmon can evolve into Alphamon via DP, ignoring type, since it’s in the evo-box. Ignoring type here is a game rule, not an effect so it can ignore Ruler.
Only Tankmon, Veedramon, Angemon, and Cupidmon can evolve into Magnamon via DP. There are no Ruler Level C or R.
You can use “Plug-In M” to evolve to Magnamon, since it ignores Ruler specifically.
You can change your active’s name such as with “Masquerade” and evolve to Magnamon from a Level C, since you must still respect level.
Dominion: You can only change (read: add/remove) other types on your own turn, once per turn before the Strategy Phase.

Changing Types?

Since you can never lose once you’re printed with it, how does “changing” types work? In addition, what’s all this about a once-per-turn-something-or-other ability? Let’s start with what happens when you “change” a Ruler’s type:

Both players have chosen their attacks. You, with Magnamon, and the opponent move into the Support Phase. Your opponent supports with Mystery Egg, looking to mooch off of your higher level and set up “ x3 VS” on their ability. Since you can’t lose , you simply gain the type. Attacks have been chosen, so Dominion can’t remove the type. You will likely get hit for triple damage.

Later in the game, you draw Scummon’s Curse, activating its effect to change your type. Since you can’t lose Ruler, and you must “change” a type, the only remaining conclusion is that your extra Enigma typing now becomes one of your choosing. You pick , since your opponent doesn’t appear to have any “x3 VS” abilities for it and you cannot simply drop the Enigma type with this card effect. You are safe for now. ~Change Ruler's Type Example

Hopefully this example hit every case that might be confusing. The simplest rule is: you won’t ever lose Ruler. “Change” adds the type if you have no others, then actually changes the non-Ruler type(s) if you have them.

Special Ability: Dominion

Let’s say you have evolved a Plottmon into Cupidmon, then ultimately into Magnamon. Now, you would like to evolve into the MetalGarurumon in your Destiny Zone. Right now, Magnamon is only . It would need to add or in order to make the evolution, assuming you have some way of achieving/bypassing the 50DP requirement. Before you choose attacks (Strategy Phase), you can, once this turn, add either the printed type of Plottmon or Cupidmon to Magnamon. Cupidmon won’t help here since it’s , but Plottmon works! You change your type to Nature, and now you’re ready to evolve to MetalGarurumon. You can’t change your type again this turn with the Ruler ability “Dominion”. Now that you are Metalgarurumon, you are not a Ruler and do not have Dominion. ~Dominion Example

You can also remove the types instead! Dominion is a powerful ability intended to enable special effects and in some cases, evolution. Since you can only use (printed) types in your active zone, it’s good to design your deck with the correct types in mind, then use Dominion only when Rulers would otherwise interfere with the natural course of the deck.

Ruler-Card Tendencies

Basic tendencies Rulers currently (and probably in the future) have:

Currently and in the planned future, there are no Level R or C Rulers. This could cause problems with the balance of the game and be difficult to integrate into decks. It would also ruin some of the design space.
Rulers will not be as commonly printed or fully-supported as a “type”. Mostly due to the above reasons. This retains their speciality.
Rulers tend to be more powerful, not necessarily with their Support ability, but their bodies (Power and HP) tend to be higher since the evolutions are more difficult. This is a common theme with difficult evolutions.
Their DP requirements are planned to be, and remain, high for the foreseeable future. 50DP or higher.
Reprints of existing cards into Ruler are planned. So far, Knightmon and Rapidmon are confirmed as future Rulers. (Released in RD)
They will not be in every set going forward, unless necessary.
You won’t see every traditional “Virus Buster” as Ruler. That’s why the name changed. These are not virus busters.