When this card is Summoned, declare different Monster Card Attributes equal to the number of "Disciple of the Forbidden Spell"(s) in your Graveyard. If this card attacks a monster that has a declared Attribute, destroy the monster with this card's effect without applying damage calculation.
And watch as they survive with Neos Fusion, Fuma or Shi En's effect and you lose a bunch of LP for no reason. Or they just Bacon Saver or Enemy Controller and attack over it. Or they just let you 🔥 their thing and then attack over it.
I wasn't saying Shi En can negate Disciple. I was saying it can destroy another Six Samurai instead.
And yes, baiting those things out is a thing you can do. But there are also much better cards that can destroy things like Shi En or Brave Neos that don't require set-up. Why should I use Disciple over a card like Cipher Soldier, Golden Dragon Summoner, Snipe Hunter or Koa'ki Meiru Ice?
Combine with Needlebug Nest and Tribute to the Doomed to get the full effect.