Neat idea. There's some commons/uncommons out there that are pretty good when they die: Jeskai Sage, Palace Familiar, Black Cat. They are nice little exploit targets, and also keep your opponent from wanting to attack sometimes.

You should double up on some of your better cards if you can. 2 Anglers and 2 Anticipate, maybe getting rid of dome Mirror Mockerys

I would try to get more multiples of cards. It makes your deck more consistent in how it plays every game

This is actually pretty cool. A tip also is that when you enchant a creature with Mirror Mockery, you can exploit the token that it generates every time it attacks so you don't have to lose your permanents. I like this idea a lot.

I think that a fun way to go with this deck for some casual games, at least if you want to go with the Mirror Mockery theme would be to add Sidisi, Undead Vizier because I think that even though she is a legendary creature, when you make a copy of her with mirror mockery you can just exploit the copy itself allowing you to effectively tutor for the cost of a Mirror Mockery and attacking (although she is a hard creature to block effectively because of her deathtouch) this combo may not work, though but I think it does. Also, she is not to expensive as you would only need one or two copies at around five bucks a piece.

bantenchanter After some research, I found that Sidisi, Undead Vizier and any legendary creatures can't benefit from Mirror Mockery

Replace the Evolving Wilds for Temples.

I would think about dumping stormtide leviathan in favor of 2 more black cats, this would lower your over all CMC and make the deck run a bit faster, plus you would have more useful sacrifice fodder for your combos. I would also think about dumping AEtherling as he does not do that much for your deck and is a high CMC, I would reccomend either another profaner of the dead or perhaps something like shrieking affliction. looks like a good jumping off point

You might want to take out the guildgates for Temple of Deceit, Ponder is a 1 mana version of Anticipate, Id take out the AEtherling and Stormtide Leviathan for something like Scuttling Doom Engine or some other creature that does something when it dies. Reassembling Skeleton is good tribute fodder. Dragonlord Silumgar to sac your opponents creatures. As far as I know, you don't have any ways to get creatures to sacrifice when you copy your exploit creatures

Srlqulongtard Thanks for the suggestions, i won't be using Temple of Deceit because its out of my budget right now. But I'm trading Dimir Guildgate for Jwar Isle Refuge. I'm planning on taking out Stormtide Leviathan for Abyssal Persecutor.Dragonlord Silumgar is out of my budget too :/

About Reassembling Skeleton maybe I place him on Black Cat spot?

Tenacious Dead and a sac outlet I am partial to Bubbling CauldronNezumi Bone-Reader Viscera Seer

Brainstorm is very powerful, and also very cheap. Doom Blade is better than Terror in my opinion. Mana Leak is a good counter. some fun counters would be Spelljack and Counterlash. A more objectivly good counter would be Dismiss.

also Murderous Cut is very efficient.