3 "HERO" monsters During the turn this card was Fusion Summoned, its ATK is double its original ATK. This Fusion Summoned card can attack 3 times during each Battle Phase. This card cannot attack your opponent directly.
These HERO monsters have effects that can search for a Polymerization from your deck, making fusion into Trinity easier since they can also be used as part of the material. They don't necessarily pair well with each other but they each provide other benefits. Woodsman can also be used to fuse for Elemental HERO Terra Firma, Blazeman can either get Polymerization or increase its attack by sending an E Hero from your deck to the GY, Vyon's effect to send any HERO monster from the deck to the GY can be useful to set up for some plays. The main downside is that both Vyon and Blazeman are from structure decks, so getting more than 1 copy requires in-app purchases.
Since it's treated as a Destiny Hero Monster on the field, it can be used to fuse into trinity by activating its effect and summon 2 others to the field. It can't be used as fusion material from your hand since it's not considered a HERO monster.
I kinda want Edge Hammer, actually. (That reminds me, though... Why the heck don't we have Bladedge yet? Hopefully we get another LD drop expansion at some point that gives Jaden Bladedge and Wildedge.)
It's confusing to me too. I understand why King of the Swamp doesn't work, it says it only substitutes for a specific fusion material whose name is on the card. But usually a fusion monster card will specify "must be fusion summoned with the above fusion material monsters" if it is to restrict what you can use.
example : ultimate agg "agg + 2 ancient gear" you can use fusion sub to replace agg but you cant use it to replace 2 ancient gear monster
There's something wrong here. D Cubed can only be used for summoning DESTINY HERO monsters. So i think we CAN'T use it for summoning Vision HERO Trinity, bc he's not a DESTINY HERO monster. That's right?
Not the only thing wrong there, since only the Normal Summoned one can even treat itself as a HERO in the first place. That being said, they're not COMPLETELY incorrect, you could use it as a material for Trinity if you didn't use the Summon effect, or in a later turn even if you did.
The main purpose of D Cubed is clearly Destiny HERO - Dogma rather than anything else.