These are defective

[Toffee.]

If this card is Summoned, you can place the top card of your deck face-down under this card. This card gains 100 ATK for each card under this card. Once per turn you can place 1 card from the top of your deck face-down under each of your face-up "Defective" monsters that you currently control. Once per turn, if the opponent activates the effect of a Spell or Trap Card, you can return a total of 3 cards from under face-up "Defective" cards(s) you control to the bottom of your Deck: Negate that effect. If this card is removed from the field or used as an Xyz Material monster, return all cards under this card to the bottom of your Deck.

If this card is Summoned, you can place the top card of your deck face-down under this card. This card gains 100 ATK for each card under this card. If this card is removed from the field by your opponent's card(either by battle or card effect): You can Special Summon 1 "Defective" monster from your Deck. Then, place the top 3 cards of your deck face-down under the Summoned monster. If this card is removed from the field or used as an Xyz Material monster, return all cards under this card to the bottom of your Deck.

If this card is Summoned, you can place the top card of your deck face-down under this card. Once per turn, you can place the top card of your deck face-down under this card: This card gains 500 ATK until the End Phase. This card gains 100 ATK for each card under this card. If this card destroys an opponent's monster by battle, you can Special Summon 1 "Defective" monster from your Deck. The Summoned monster cannot attack this turn. If this card is removed from the field or used as an Xyz Material monster, return all cards under this card to the bottom of your Deck.

If you control a Level 3 "Defective" monster with 3 or more cards under it, you can Special Summon this card from your hand or Graveyard. Then, place 1 other face-up "Defective" monster you control, and all cards under it, face-down under this card. This card gains 200 ATK for each card under this card. This card is unaffected by the effects of Trap Cards. Once per turn you can place 2 cards from the top of your deck face-down under a face-up "Defective" card that you currently control. If this card is removed from the field or used as an Xyz Material monster, return all cards under this card to the bottom of your Deck. You can only control 1 "Defective Virus".

If you Normal Summon a "Defective" monster, you can Discard 1 Spell card: Add this card from your Deck to your hand. You can only activate this effect of "Defective Network" once per turn. When this card is activated: Place the top 2 cards of your Deck face-down under this card. "Defective" monsters you control gain 100 ATK for each card under this card. If a "Defective" monster declares an attack, or is selected as an attack target, you can place the top card of your Deck face-down under this card. This card cannot be Targeted by your opponent's card effects. If this card is removed from the field, return all cards under this card to the bottom of your Deck.

Target 1 face-up "Defective" card you control with at least 1 card under it: Reveal all card(s) under the Target. Then, add to your hand 1 of the revealed cards. Then, return the Target and all cards under it to the bottom of your Deck. Then, Draw 1 card. You can only activate 1 "Defective Code" per turn.

Pretty much the idea behind these was that they fill the Graveyard, without actually doing it, and in turn, end up as a bunch of weird Shadow Ghouls. Concept wise, they are basically corrupted files n' junk, to which, get worse(IE, infect more stuff) the longer they stay out, to the point of it being unrepairable(Virus, for example).
Also these have a hint of Summer Wars in them.
...Not that it's relevant or anything.

[Progenitor]

I think there are a couple of general OCG errors, of which I am no expert, but one thing you do need to specify is the order of the cards sent to the bottom.  Is it the same order in which they were attached, or does the player get to choose?  If they can choose, do they get to look at the cards?

[Toffee.]

I think there are a couple of general OCG errors, of which I am no expert, but one thing you do need to specify is the order of the cards sent to the bottom.  Is it the same order in which they were attached, or does the player get to choose?  If they can choose, do they get to look at the cards?

Part of this, is because I thought the return effect would be similar to Ehren, in that sense that it just gets executed as-is, and nobody looks at them.

[Trebuchet MS]

Here I come to fix the OCG.

 

[spoiler Arms]If this card is Summoned: You can place the top card of your deck face-down under this card. This card gains 100 ATK for each card under this card. Once per turn: You can place 1 card from the top of your deck face-down under each of your face-up "Defective" monsters that you currently control. Once per turn, during either player's turn, if the your opponent activates the effect of a Spell/Trap Card: You can return a total of place 3 cards from under face-up "Defective" cards(s) you control to on the bottom of your Deck in any order; negate the activation that effect. If this card is removed from leaves the field or is used as an Xyz Material monster, return place all cards under this card to on the bottom of your Deck in any order.[/spoiler]

 

[spoiler Guard]If this card is Summoned: You can place the top card of your deck face-down under this card. This card gains 100 ATK for each card under this card. If this card is removed from leaves the field by your opponent's card(either by battle or card effect): You can Special Summon 1 "Defective" monster from your Deck, then, place the top 3 cards of your Deck face-down under the Summoned monster. If this card is removed from leaves the field or is used as an Xyz Material monster, return place all cards under this card to on the bottom of your Deck in any order.[/spoiler]

 

[spoiler Sword]If this card is Summoned: You can place the top card of your deck face-down under this card. This card gains 100 ATK for each card under this card. Once per turn: You can place the top card of your deck face-down under this card; this card gains 500 ATK until the End Phase. If this card destroys an opponent's monster by battle: You can Special Summon 1 "Defective" monster from your Deck, but the Summoned monster cannot attack this turn. If this card is removed from leaves the field or is used as an Xyz Material monster, return place all cards under this card to on the bottom of your Deck in any order.[/spoiler]

If a battle reversal occurs during the opponent's Battle Phase and this card destroys an opponent's monster due to that, I still get to Special Summon. Is that intended?

 

[spoiler Virus]If you control a Level 3 "Defective" monster with 3 or more cards under it, you can Special Summon this card (from your hand or Graveyard). Then, place If this card is Summoned this way: Target 1 other face-up "Defective" monster you control; place that target, and all cards under it, face-down under this card. This card gains 200 ATK for each card under this card. This card is unaffected by the effects of Trap Cards. Once per turn: You can target 1 face-up "Defective" card you control; place 2 cards from the top of your deck face-down under that target a face-up "Defective" card that you currently control. If this card is removed from leaves the field or is used as an Xyz Material monster, return place all cards under this card to on the bottom of your Deck in any order. You can only control 1 "Defective Virus".[/spoiler]

Hello again, Melnia! Oh, how I have missed you. You're still my favourite DM card.

 

[spoiler Network]If you Normal Summon a "Defective" monster: You can discard 1 Spell card; add this card from your Deck to your hand. You can only activate this effect of "Defective Network" once per turn. When this card is activated: Place the top 2 cards of your Deck face-down under this card. "Defective" monsters you control gain 100 ATK for each card under this card. If a "Defective" monster declares an attack, or is selected as targeted for an attack: target, You can place the top card of your Deck face-down under this card. This card Cannot be targeted by your opponent's card effects. If this card is removed from leaves the field, return place all cards under this card to on the bottom of your Deck in any order.[/spoiler]

The auto-tutor effect seems hard to phrase (and nearly problematic), since it's nearly unheard of to activate card effects from the Deck.

 

[spoiler Code]Target 1 face-up "Defective" card you control with at least 1 card under it; reveal all card(s) under that target, then, add to your hand 1 of the revealed cards to your hand, then, return place that target and all cards under it to on the bottom of your Deck in any order, then, draw 1 card. You can only activate 1 "Defective Code" per turn.[/spoiler]

So many actions in sequence! Thankfully your cards are phrased to never miss the timing.

 

Ultimately, this is a very interesting archetype. Like Hideaway worked into YuGiOh. It'd also be curious if you somehow eventually make an Xyz monster for Defectives. I'd like to see how you differentiate between Xyz Materials and cards placed underneath it via Defective effects.