A couple of XYZ's

[BoricuaBeast]

I added a spell for the lulz...

 

 

Lore: 

3 Level 8 LIGHT monsters

When this card is Special Summoned, you can select 1 face-up card your opponent controls: negate that card's effect(s) until the End Phase. Once per turn, you can detach 1 XYZ material from this card and target 1 other monster you control, that monster is unaffected by the effects of Spell & Trap cards until the End Phase.

 

Lore:

Target 1 face-up LIGHT Xyz Monster you control; Special Summon from your Extra Deck, 1 "Number C" or "Cxyz" monster with the same Type and Attribute as that monster you control, but 1 Rank higher, by using it as the Xyz Material. (This Special Summon is treated as an Xyz Summon. Xyz Materials attached to it also become Xyz Materials on the Summoned monster.) The monster summoned by this effect gains 2000 ATK. That monster cannot attack directly this turn. During the End Phase, reduce that monster's ATK to 0, then you take damage equal to it's rank x800

 

Lore:

4 Level 9 monsters

When this card is Summoned, destroy all set Spell/Trap cards on the field. When this card declares an attack, your opponent cannot activate Spells or Traps until the end of the Damage Step. If this card has "Cosmic Knight" attached as XYZ material, it gains the following effect:

- Once per turn, you can detach 1 XYZ material from this card, negate the effect(s) of 1 face-up monster your opponent controls and that monster's ATK becomes 0. This card cannot attack during the turn you use this effect. 

[goddamnit names are a pain]

I think this concept has potential. Maybe you should lose Lifepoints rather than have them as damage, because that could be "worked" around. Also, when you play the Cxyz's effect, the Rank Up becomes quite useless. Finally, I would alter the effect of the CXyz a little. Blowing up all set spells and traps and still being able to attack without issues seems a little OP. Maybe change his effect to something like "cards can not be activated upon this card's summon." I know, horrible OCG, but you know what I mean.

[BoricuaBeast]

 Maybe change his effect to something like "cards can not be activated upon this card's summon." 

That sounds even more OP. Having a 3800 beatstick that you can't bottomless or torrential would be unfair as hell. On top of the effects of RUM cards? That's why I had it like that. 
However, you do have a point on the spell. I'll change that later.