I also need to nerf its cast point.

Frost Armor
Artifact - Equipment
Equipped creature gets +0/+3.
Whenever equipped creature deals combat damage to a creature, tap that creature. It doesn't untap during its controller's next untap step.
Equip

Static Field
Enchantment
Whenever you cast an instant or sorcery spell, ~ deals 1 damage to each creature and each opponent.

Static Field needs to scale.

I considered that but realized that it would be awkward to implement for creatures. So how about you just pretend it's Raigor's passive instead?

Reflection
Instant
Put a token onto the battlefield that's a copy of target creature attacking you. Sacrifice it at end of turn.

This is pushing the boundaries for blue. I would be a lot more comfortable if it was .

Magic isn't any fun unless you can cause people discomfort.

Disable
Instant
Target creature loses all abilities until end of turn.
Draw a card.

That ability seems philosophically green to me.

Also, it would be cool to use "Choose a creature..." wording so you can get around hexproof.

Avalanche // Toss //
Instant
Until end of turn, whenever a creature enters the battlefield under an opponent's control, ~ deals 3 damage to it.
//
Exile target creature, then return it to the battlefield under it's owner's control.
Fuse

Ghost Scepter
Equipment
: Prevent all combat damage that would be dealt to and dealt by equipped creature this turn.
Equip

Astral Imprisonment
Instant
Draw a card, then target player discards a card. That player gains shroud until end of turn.

Mana Break
Enchantment
Whenever a creature you control deals combat damage to a player, tap target land that player controls. It doesn't untap during its controller's next untap step.

Grand Magus
Creature - Human Wizard
Whenever an opponent casts an instant or sorcery spell, you may exile that spell as it resolves.
, , discard a card: copy a card exiled with ~ with converted mana cost x. You may cast the copy without paying its mana cost.
2/4

Avalanche // Toss doesn't seem like a split card name, unless there's some DotA reference I'm missing.

Ghost Scepter could be confusing for new players. I suggest making it a mana activation.

I don't get the flavor of Astral Imprisonment. Giving your opponent shroud also seems counterintuitive.

Mana Break is horrible and you should feel horrible.

Grand Magus could say "...you may have that spell be put into exile instead of its owner's graveyard as it resolves."

They're all DotA references.

Avalanche is cool, feels like a red Essence Scatter, and the fuse works well.

Astral imprisonment can be used on yourself to counter a spell but seems much more likely you just cast it on your opponent, especially since it's an instant so you can do it during their draw step.

I used the wording from rebound for grand magus.

The flavor of astral imprisonment is that you can imprison yourself defensively.

Ghost Scepter would suck if you had to pay mana to use it.

Mana Break: the fun ends here.

Curse of the Silent
Enchantment - Curse Aura
Enchant player
At the beginning of enchanted player's upkeep, that player sacrifices a land and ~ deals 2 damage to that player.
Whenever enchanted player casts a spell, sacrifice ~.

Abandon
Instant
Remove target creature from the game. That creature's controller distributes a number of +1/+1 counters equal to its power among creatures they control.

Feels like abandon makes more sense flavorfully if it focuses on the toughness number rather than the power. Of course, that's just an uneducated, out-of-touch, terrible player's opinion. Hey, Cato.

Haven't seen you in a while. What brings you to the boards?

A deep yearning for forum mafia. Thought I'd look in on YMtC while I was at it.

Cool.

Devourer of Souls
Creature - Demon
When ~ enters the battlefield, any opponent may sacrifice x creatures. If they do, sacrifice ~.
3/3

The card reads as interesting but is not actually that interesting in practice. Most of the time it's going to be Centaur Courser. You would really only get value out of it against a creatureless deck.

I mean, they can sac 2 1/1s to counter it, or you could use it as a 3/3 if they don't have any creatures less valuable than it.

In my opinion, the card would be much more interesting as a 4/4 flier for .