While "Fusion Destiny" (as well as "Destiny HERO - Doom Overlord") locks the player out of Special Summoning non-DARK "HERO" monsters, most of the consistent "HERO" extenders and strong endboard pieces (i.e., all "Vision HEROes", "Masked HERO Dusk Crow", "Masked HERO Dark Law", "Masked HERO Anki", "Contrast HERO Chaos", and all "Xtra HERO" monsters sans "Xtra HERO Wonder Driver") are "DARK", so "HERO" decks can still build a competent field even if the player has to use "Fusion Destiny" as their early combo starter
Final point of note is that Agent is an artifact which increases his potential synergies while not being an issue in regards increase susceptibility to removal as you don't overly care about the body once you have cast it
Though, if selfishness is a crime then black is the worst offender seeking greatness at any cost
No matter how solid your board is, it will all be swept away by "OP01-094 Kaido"
if this is your first time with the app, youll need to set your account up and itll definitely help if you play through the somewhat lengthy tutorial first, to ensure youve unlocked all of the free decks and cards that the MTG Arena app will add to your account