Some Trolly Rock-Types and Support [?/?]

[Kingdom Xathers]

Once per turn, this Defense Position card cannot be destroyed by battle. When this card is flipped face-up: Target 1 face-up monster on the field; change its battle position.




You can Set this card from your hand to your Spell & Trap Card Zone as a Spell Card. During the End Phase of the turn this Set card in your Spell & Trap Card Zone was destroyed by an opponent's card effect and sent to the Graveyard: Target 1 Spell or Trap Card your opponent controls (if possible); destroy it, and if you do, you can Special Summon 1 Level 4 or lower Rock-Type monster from your Graveyard in face-down Defense Position.




When this card destroys a monster by battle and sends it to the Graveyard: You can send 1 Rock-Type monster from your Deck to the Graveyard. When this card is sent to the Graveyard by your opponent (either by battle or by a card effect): Target 1 Rock-Type monster that was sent to your Graveyard by this card's effect; Special Summon that target in face-up Defense Position.



More to come later (hopefully).

[Zazubat]

I like these a lot. They are fairly balanced, support Rock-Types greatly, and rock pretty well together. I wish for them to be an Archetype though, and feature a form of boss outside general support though, as right now, they seem like they would help Rock decks a lot, but still wouldn't really give them the right amount of push they are required. Anyway, let's go over them 1 by 1, so I can show you why I like them:
 

Ryu:

It's a better Gogogo Golem. The nice thing about this is that when it's flipped face-up, it changes a monster that might be able to destroy it, which helps it keep itself alive. It go nice stats, making it useable by plenty of cards, and it's Attribute works well for Rocks. Your OCG is flawless as well, so good on you.

 

Eater:

It's pretty creative. It could be considered powerful on paper, being a monster which also Special Summon something and , but really, you gave it the right amount of things it needed with having it only be from your opponent, and it being Summoned mandatorily during the End Phase, so you might end up losing that monster right away, before you can do much which it. The face-down is interesting actually, since that supports flipped face-ups and FLIPS as well. It helps Ryu out by putting in DP actually, which is quite handy, as well as other Rocks that like being in DP.

OCG is flawless again, though you would normally change the Spell or Trap Card to say Spell/Trap Card, though that's not a dealbreaker.

 

Dustborn:

Another interesting card. While it might not ending up being very useful most of the time, since destroying monsters is hard to come by, it can get a ton of powerful Rocks, though it is still balanced by the Defense Position and the must be destroyed and sent to the Graveyard as well, so Macro can mess with it. It's useful when you can get it going, but also balanced enough to not make it broken. Good job again.

Nothing wrong with the OCG, but after the "your opponent", there should be the word "card", which I just assume you missed putting in.