Monster Union set

[Thomas★Zero]

Star Wing Dragon
Lv 4 Light
Machine/Union
Once per turn, you can equip this card to a monster you control, OR unequip it to Special Summon this card in face-up Attack Position. While equipped to a monster by this effect, when the equipped monster destroys a monster as a result of battle, banish 1 card in your opponents hand and if that card is a monster inflict 300 x the level of that card. (A monster can only be equipped with 1 Union Monster at a time. If the equipped monster would be destroyed by battle, this card is destroyed instead.)
ATK/1800 DEF/1200

Xyz Armour
lv 4 Earth
Warrior/Union
Once per turn, you can equip this card to a Warrior-Type monster you control, OR unequip it to Special Summon this card in face-up Attack Position. While equipped to a monster by this effect, if the monster equipped with this card levels is the same as this card you can unequip it to special summon it this turn in face-up Attack Position. (A monster can only be equipped with 1 Union Monster at a time. If the equipped monster would be destroyed by battle, this card is destroyed instead.)
ATK/0 DEF/0

Heavy Mobile Armour - Iron Red Knight
lv 8 Fire
Machine/Union
Once per turn, you can equip this card to a level 4 or lower monster you control, OR unequip it to Special Summon this card in face-up Attack Position. While equipped to a monster by this effect, the equipped monster gains 1000 ATK and 2000 DEF. (A monster can only be equipped with 1 Union Monster at a time. If the equipped monster would be destroyed by battle, this card is destroyed instead.)
ATK/1000 DEF/2000

Holy Pegasus Chariot
lv 6 Light
Fairy/Union
Once per turn, you can equip this card to a Fairy-Type monster you control, OR unequip it to Special Summon this card in face-up Attack Position. While equipped to a monster by this effect, you can reduce the monster equipped with this cards ATK by 1000 so it can attack directly this turn. (A monster can only be equipped with 1 Union Monster at a time. If the equipped monster would be destroyed by battle, this card is destroyed instead.)
ATK/1000 DEF/1000

Tamed Sky Dragon
lv 4 Wind
Dragon/Union
Once per turn, you can equip this card to a Warrior, Beast-Warrior or Spell caster-Type monster you control, OR unequip it to Special Summon this card in face-up Attack Position. While equipped to a monster by this effect, when the equipped monster battles a monster your opponent controls it becomes unaffected by any effects that monster may have. (A monster can only be equipped with 1 Union Monster at a time. If the equipped monster would be destroyed by battle, this card is destroyed instead.)
ATK/1400 DEF/1600

[newhat]

What is the point of Xyz Armour? You would have to control the monster to Unite it.

 

All of these need some kind of acceleration to get them onto the field; this has always been the problem with Union monsters.

[Thomas★Zero]

With Xyz Armour note this...
"
While equipped to a monster by this effect, if the monster equipped with this card levels is the same as this card you can unequip it to special summon it this turn in face-up Attack Position."

 

This means when equipped to a monster of a matching level this effect would kick in so unequip it and summon it during the turn you equipped it so you can have 2 Level 4 monsters on the field to make a rank 4 Xyz monster.

 

[newhat]

Advanced Clause applies to Written Cards now?

To equip it to a monster of the same Level, you would need to have Armour on the field already. You could get Armour on the field in one of three ways:

 

1: Summon it. If you do, you already control 2 Level 4 monsters, and there's no need to equip it just to unequip it again.

 

2: Attach it with Roll Out!...but you can use Call of the Haunted instead and you wouldn't need to revive Armour, just any Level 4 monster, or anything you wanted.

 

3: Equip it by the effect of Delta Tri for whatever reason. You could just use Machina Gearframe or something.

 

Am I missing something? I do not see the purpose.