when dreadmaster is special summoned from grave

will it still get to summon 2 more destiny heros from grave and will the triger effect of destroying other monsters except destiny heros apply???

no

If this card was Special Summoned by "Clock Tower Prison", destroy all monsters you control (except for "Destiny Hero" monsters), then you can Special Summon up to 2 "Destiny Hero" monsters from your Graveyard.

only if it is summoned by clock tower prison do you get 2 more d heros and loose other monsters but his other effects still apply like

During the turn this card is Special Summoned, "Destiny Hero" monsters you control cannot be destroyed, and you take no Battle Damage when they battle.

Correct. Because the card effect states that "Destiny Hero Dreadmaster" has to be special summoned by "Clock Tower Prison" in order for the effect to activate, the effect will not activate if it is special summoned from the graveyard by a different card effect.

And the second part of the answer is also correct. The other effects will activate, because they only require "Destiny Hero Dreadmaster" to have been special summoned onto the field.

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Closed.

~Aster Phoenix