Introduction

"Masked HERO" is a "HERO" sub-archetype used by Jaden Yuki in the Yu-Gi-Oh! GX manga. Jaden started using these "HEROes" after the tournament to Duel the Kaiser, when he decided to build an "all-his Deck", which would eventually grow into his ultimate Deck (since the "Elemental HEROes" he used previously were Koyo Hibiki's Deck).
The "Masked HEROes" are currently the only monsters to be able to perform Transformation Summons. While the "Elemental HERO" archetype is said to be based off of American superheroes, it can also be assumed that the "Masked HERO" archetype is a salute to Japanese Kamen Rider heroes. In addition to "Kamen" meaning "Masked", there are several similarities between the two, such the recurring "form changing" and transformations of Kamen Riders. The Double Attacks are also similar to the original Kamen Riders' (1 and 2) "Rider Double" techniques.

Archtype Cards:

Most common cards used with masked hero's:

Playing Style

Rather than Fusion Summoning like most Fusion Monsters do, "Masked HEROes" use cards like "Mask Change" to Special Summon themselves from the Extra Deck. In the manga, Chazz Princeton was amazed seeing how the "Masked HEROes" could use the same effect of "Fusion" using one single material rather than 2 or more.
This archetype favors a fairly straight-forward Beatdown strategy. Their "transforming" cards being Quick-Play Spell Cards allows them to be transformed at any time, including during the Battle Phase, for multiple attacks, or in response to an opponent's effect or attack.
While in the manga "Masked HEROes" are an independent archetype, in the TCG/OCG they were revamped to be a general "HERO" support, making them Splashable options for any "HERO" Deck (though they essentially work well only with the "Elemental HEROes", due to their varied Attributes). "Mask Change Second" takes this even further by allowing "Masked HEROes" to be splashable in any Deck, as long as one can handle the increased cost and Extra Deck real estate.
An efficient build can consist of running a few Elemental HEROes that help you conduct fusion summons (Like Elemental HERO Blazeman and Elemental Hero Woodsman) to fusion summon Elemental HERO Absolute Zero (King of the Swamp help this even further) which has 2 advantages: can be fusion summoned using even Masked Heroes, and when combined with Mask Change or Form Change, lets you get a WATER or high leveled Masked HERO while destroying your opponents' monsters.


Weakness

The variety of Types and Attributes makes the Fusion monsters vulnerable to floodgate cards like "Rivalry of Warlords" and "Gozen Match",
Aswell as the obvious choice of cards like ''Vanity's Fiend'', ''Vanity's Emptiness'', ''Non-Fusion Area'' etc that prevent Special Summons or Fusion summons.