D-Hero Diamondguy.

D-Hero Diamondguy and Cold Wave
Situation: Diamondguy sends cold wave from the top of the deck to the graveyard via his effect.
Question: Is it a must to activate the Cold Wave from the Graveyard first in order to get Cold Wave's effect?

D-Hero Diamondguy + Bonding H20 and Royal Oppression
Situation: Diamondguy sends Bonding H20 from the top of the deck to the graveyard via his effect. Royal Oppression is face-up on the field.
Question: Will the effect of Bonding H20 be negated by Oppression?

1. If you're asking if it still has to be the first thing you activate in main phase 1, yes. It is a timing requirement.

2. Yes can be negated by oppression. (At least 80% sure I think, not very sure on this one). Oppression can negate the effect of the special summoning, e.g. stardust from grave, etc. So can negate. The card does not have to be on field.

1. yes.since u have the choice whether to activate it in your grave the next turn. btw u may choose not to use the normal magic the next turn and wait to activate it at some mainphrase down the road.

2. still yes but only in the next turn. when u activate bonding. even if im wrong in this case u still can chain it to the monster's summoning.

Ok thanks for the first one. But the second one seems similar to Light and Darkness Dragon's negation effect.

LADD is totally different... LADD does not go through because it is no longer on field to reduce 500 atk/def. Diamond guy and Bonding H2O do not have such an issue