REDU format ruling
Destiny HERO - Dreadmaster

Nearest-era rulings (Tengu, Sept 2011) — no REDU-specific archive exists.
Card effect (current official text)If this card is Special Summoned by "Clock Tower Prison": Destroy all monsters you control, except "Destiny HERO" monsters, also, after that, you can Special Summon up to 2 "Destiny HERO" monsters from your GY. After this card is Special Summoned, for the rest of this turn, "Destiny HERO" monsters you control cannot be destroyed, also you take no battle damage when they battle. The ATK/DEF of this card are equal to the combined original ATK of all other "Destiny HERO" monsters you control.
Rulings
- "Destiny Hero – Dreadmaster’s" second sentence is applied if he is Special Summoned by any method, not just by the effect of "Clock Tower Prison".
- "Destiny Hero – Dreadmaster’s" first effect (to destroy your non-"Destiny Hero" monsters and Special Summon 2 "Destiny Hero" monsters) is a Trigger Effect and his other effects are Continuous Effects.
- Destroying all your non-"Destiny Hero" monsters and Special Summoning 2 "Destiny Hero" monsters is resolved in the same chain link. Even if you have no monsters that will be destroyed you still get to Special Summon 2 "Destiny Hero" monsters.
- If you have any face-down "Destiny Hero" monsters, they will be destroyed, because their names cannot be confirmed.
Rulings data courtesy of Format Library — formatlibrary.com. Spotted an inaccuracy? Flag it in the REDU forum — sourced change requests get reviewed.