If the card I send to the Graveyard with Diamond Dude's effect is Level Up! if during my Main Phase I have a Level monster on the field, can I use Level Up

Yes you can but of course you will have to wait intil your next turn.

Yes you can, as long as the requirements for the "sent" spell card are correct you would be able to use it.

When activating a Spell Card's effect via "Destiny Hero - Diamond Dude", you do not (and cannot) pay the card's cost.

So, even if you have a LV monster you wish to Tribute, you are unable to Tribute it, since you bypass "Level Up!"'s cost.

So, no matter what, "Level Up!"'s effect disappears if you attempt to activate it via "Destiny Hero - Diamond Dude"'s effect, as you have no Tributed monster to use as a frame of reference.

Guess I should've looked at the rulings =P, I overlooked the cost issue... I forgot that Diamond Dude only activates the effect of the card.

Yep Kenjiblade is right, Level Up! requires a cost, and since D-Hero Diamond Dude negates that cost it pretty much negates the effect

It doesn't negate it, it simply doesn't use costs, Diamond Dude's effect is only to activate the spell cards "effect", nothing else. This is because DDude doesn't actually activate the spell card itself.

Yeah lol, I know what you mean, I just had a bad choice of words

Yep...stuff like Level Up! and Metamorphosis won't work because not because of bypassing the cost, but because of the fact that that cost is a reference to what is to be Special Summoned with the actual effect.

Level Up! looks at what is sent to the Graveyard and acts accordingly, but since nothing is sent, there is no LV monster to make a reference to, thus no way of "knowing" what to Special Summon with it, so it doesn't do it at all.

Same with Metamorphosis except it looks for a Star Level of a monster.

man if that don't make sense, I don't know what does

that reminds me of the magic card eternal dominion (in MTG). You are allowed a card from your opponent's deck and do not pay its cost. However some cards in that game refer to "x" number of mana used for its effect. Since no mana was paid for that effect, the effect is useless.

So yeah, level up wont get its effect.

lol...a little late there....

So from what you saying HalfD. would I be correct in saying I can use the effects of these cards without meeting the activation requirements or costs?

Back To Square One
Card of Sanctity
Chaos Greed
Chaos End
Elegant Egotist
Final Destiny
Monster Gate
Multiplication of Ants
Ojama Delta Hurricane
Phantasmal Martyrs
Primal Seed
Spell Reproduction
Stray Lambs
Stamping Destruction
Tribute Doll
Ultra Evolution Pill

I just want to be on the safe side on the rulings just incase I get a Diamond Dude and want to use him in some off the wall deck ^_^.

Yes...it merely activates the Effects of cards...bypassing requirements and costs...unless the effect uses the cost as some sort of "reference" to it like...

Inferno Fire Blast
Level Up!
Metamorphosis

..and stuff like that.

However, DESPITE all that, it does not make Diamond Guy "broken" really. Can't just go throwing in a bunch of, otherwise, useless cards (for the Deck) JUST in hopes of getting them with Diamond Guy's effect (even with some "peeking" support).

I highly recommend sticking with cards you can use at other times and not JUST for the effect.

Tribute to the Doomed
Dark Core
Double Spell
Spell Reproduction
Confiscation
Lightning Vortex
Back to Square One
A Feather of a Phoenix
Monster Reincarnation
Double Attack
etc

i have a very good way of explaining it,

if what you pay for the cost, effects the effect, you cant use it,

but you can use stuff like release restraints, because it only has 1 possible cost,

remember if cost effects effect, no, (i memerized this when i used serial spell, lol)