Target 1 face-up monster you control; add up the total ATK of all other face-up Attack Position monsters you currently control, then during the Battle Phase of this turn only, the monster gains that much ATK, but cannot inflict battle damage to your opponent, also other face-up Attack Position monsters cannot attack.
Good for taking down monsters with higher attack when you have more monsters.
Needed in some farming decks, and very effective if used properly.
Limited usability since it can only be used to destroy enemy monsters but not able to deal damage to LP.
Only selected monster can attack.
Tips, related cards, skills
A well known popular combo is Gravekeeper's Vassal with 2 monsters with a total attack of at least 4400 ATK to achieve the "Over 5,000 Damage" assessment. As of now, Gravekeeper's Vassal is the only card that has perfect compatibility with Union Attack as it nullifies the drawback effect of Union Attack.
Since this card deals effect damage, it can be used together with Union Attack to deal some damage. Used to farm some LD because it can get a high score quite easily by using 2 monsters with high attack, and end the duel with effect damage ONLY.
If you only have 1 Union Attack, you can use spell reclamation so you can use it twice. This will make it so that you can reach 10,000 damage if your total monster's attack is at least 5,000. If you have 2 union attack, then use 2 instead of this.
I fin ally got this from the Duelist Kingdom event, my 1st and only one. A few mins later I did a batch convert by card name and to keep 3 of every card and it got rid of it! Can somebody please explain this?
Batch convert only converts N and R cards, so it shouldn't have touched a SR card like union attack. The rewards for clearing X number of rounds are sent to your mailbox so you need to retrieve them before they'll show up in your possession. Was the Union Attack you had the reward for clearing round 3?