Iron Chain Boss Monsters.

[Lunar Origins]

[b][color=#ff8c00]Iron Chain Ouroboros[/color][/b]
[b][ Level 8 / Earth ][/b]
[b][ Reptile / Effect ][/b]
This card is treated as being Level 4 while in your Graveyard. You can Tribute 1 "Iron Chain" monster you control; Special Summon 1 Level 4 or lower "Iron Chain" monster from your Deck, then send the top 3 cards of both player's Decks to the Graveyard. Your opponent cannot target cards in their hand or Graveyard. You can only activate the effect of "Iron Chain Ouroboros" once per turn.
[b][ ATK: 2600 / DEF: 1900 ][/b]

[color=#006400][b]Iron Chain Ragnarok[/b][/color]
[b][ Rank 8 / Earth ][/b]
[b][ Dragon / Xyz / Effect ][/b]
[b]2 or more Level 8 monsters[/b]
Once, during either player's turn: Detach 1 Xyz Material from this card; Negate the activation of an opponent's Spell/Trap card and destroy it. Then, send the top 3 cards of their Deck to the Graveyard. While this card has an Xyz Material attached to it, your opponent cannot target cards in their hand or Graveyard.
[b][ ATK: 3000 / DEF: 3000 ][/b]

[Agro]

The ability that doesn't allow targeting is a bit overdoing it, don't you think?

If I were you I'd take that off and give it a little more ATK. After all Iron Chain Dragon, which is Level 6, has 2500 ATK with a boosting ability.

[Lunar Origins]

It makes milling viable while not restricting the Graveyard too much.

And...

eh, I like the attack where it is.

[Agro]

The milling is necessary, but the restrictions is not. It's basically trying to be Necrovalley.

And don't put "or more" cards like that need some sort of restrictions on them.

[Premier Alexander Romanov]

Doesn't the Iron Chain archetype have Dragon?
What's the point of these cards?
And who is the other LV8 for the Xyz?

[shelds9]

^^ Anyone

Pretty good cards, they are not too strong, but one thing. Iron Chains focus on Milling, so would the Boss Monsters want to have Continuous Milling effects, not only when an opponent activates a card, and only twice?