Greninja V-Union

Date Reviewed:
October 29, 2021

Ratings Summary:
Standard: See Below
Expanded: See Below

Ratings are based on a 1 to 5 scale. 1 is horrible. 3 is average. 5 is great.

Reviews Below:

Otaku Avatar

It’s time for Greninja V-Union (SW – Black Star Promos SWSH155)!  As the V-Union mechanic is still new, let us start with that.  Here’s the article explaining it on the official Pokémon site.  If you can’t or won’t read that, Pokémon V-Union are the latest addition to Pokémon V.  That means anything that apply to Rule Box Pokémon or Pokémon V will apply to Greninja V-Union.  Think of V-Union as a way for those oversize promo cards to be legal for competitive play.  This is done by dividing the one oversize card into four individual, regulation size cards.  All these pieces have the card name, Pokémon type, Stage of Evolution, and Rule Box for putting a V-Union into play on them.  These are the only things that the game recognizes when a V-Union isn’t in play.  Things that are only found on a single card, like the HP are not recognized by the game.  So, for example, you cannot use Level Ball on the pieces that lack HP scores, and you cannot use Heavy Ball even on a piece that has a Retreat Cost of [CCC].

All four pieces of a V-Union have the same name, so they count against each other for the four copy rule.  That means you’ll need one copy each of Greninja V-Union (SW – Black Star Promos SWSH155), Greninja V-Union (SW – Black Star Promos SWSH156), Greninja V-Union (SW – Black Star Promos SWSH157, and Greninja V-Union (SW – Black Star Promos SWSH158) if you want to actually put Greninja V-Union into play.  The only way to do that is to have all four of those pieces in your discard pile and an open space on your Bench.  On your turn, you can then put all four pieces of that V-Union into play, assembling them into one over-sized Pokémon!  However, this can only be one once per game per V-Union.  So you can run two different V-Unions and put them both into play, once after the other, if all these conditions are met, but you cannot put the same one into play over and over again.

“V-Union” is its own Stage of Evolution and not just a Rule Box mechanic, not unlike Pokémon VMAX.  Unlike Pokémon VMAX, Pokémon V-Union are neither Basic nor Evolution.  For example, this means you can fetch a V-Union piece from your deck with Ultra Ball but not with Quick Ball or Evolution Incense.  You cannot do anything with a Pokémon V-Union piece that requires a “complete” Pokémon i.e. you cannot put a single piece of Greninja V-Union, even if you have an effect that would normally let you put a Pokémon into play.  They’re like BREAK Evolutions in that respect.  Pokémon V-Union are worth three Prizes when KO’d.  Greninja V-Union is a Water Pokémon, which is reasonably good.  This means Greninja V-Union is compatible with the Ability of Frosmoth, as well as the effect of Melony.

Greninja V-Union’s HP, Weakness, Resistance, and Retreat Cost are found on other pieces.  So are its other effects: all that is left on this card is the “Union Gain” attack.  Priced at [C], this lets you attach two Water Energy from your discard pile to Greninja V-Union itself.  Yes, Pikachu V-Union has the same attack, except attaching Lightning Energy and – spoiler – the same goes for Mewtwo V-Union and Zacian V-Union.  Apparently, all Pokémon V-Union have this attack on the piece featuring their name.  As with Pikachu V-Union, this isn’t a good attack but it can come in handy if you’re desperate or if you’re sure that Greninja V-Union won’t be attacked for damage next turn.  Maybe even if Greninja V-Union will only take a little damage.  Peeking ahead, we can see that Greninja V-Union has an attack it can use for just [W], while the other two attacks cost [WWC].  As long as the other single-attachment attack is decent, you’ll have even less of a reason to use Union Gain.

Glancing at the rest of the card, I think Greninja V-Union has decent prospects of being a competitive card.  Maybe even more than decent.  This first piece doesn’t do much for it, however.  In Expanded, unless they eventually ban it, Battle Compressor is a V-Union’s best friend.  Battle Compressor is an Item card that lets you send three cards from your deck to the discard pile, getting you 75% of the way to a V-Union.  Max Potion is another important card; it doesn’t work well with Union Gain, but it should be “okay” with that other attack we’ll be covering on another Greninja V-Union piece.


  • Standard: 2/5
  • Expanded: 2/5

We would love more volunteers to help us with our Card of the Day reviews.  If you want to share your ideas on cards with other fans, feel free to drop us an email.  We’d be happy to link back to your blog / YouTube Channel / etc.   😉

Click here to read our Pokémon Card of the Day Archive.  We have reviewed more than 4700 Pokemon cards over the last 20 years!