Feln Unseen Beatdown (aggro/tempo)

Welcome readers!

Ive been tinkering with the "Midnight Raid" precon deck and found this configuration fun and competent enough against most decks in ranked play.

Contents
1. Introduction
2. Card Choices

1. Introduction
Its a Feln tribal themed (Unseen) deck that capitalizes on nightfall mechanics.

"Nightfall: The first Nightfall card played in a turn makes it Night and extends it by a turn for each player.
Night: When you start a turn at Night, draw an additional card and take 1 damage".

Each Unseen adds abilities and power in this deck and has a unique ability of either activating Nightfall upon hitting the ground and creating board advantage or benefit from the many curses in your arsenal. This deck has a potential to emerge into the competitive scene with its flexibility.

Why play Feln Unseen? How does it play?
Unseen are Shinobi/Ninja (Cool) and they are a sneaky bunch. They can play out quick and aggressive (aggro), or out-maneuver the opponent with the Unseen paired with cheap fastspells, aegis and evasion for a more tempo oriented approach that can thwart many various decks.

2. Card Choices

Power
Primal Sigil and Shadow Sigil - Feln colours obviously
Common Cause - Because we are tribal
Can be replaced with Diplomatic Seal
Seat of Cunning - Good influence source specially because were running a good number of sigils
Feln Banner - Good influence source specially because were running a good number of units
Amethyst Waystone - Another Nightfall trigger

Spells
Vara's Intervention - Very good utility.
Annihilate - fast and reliable although restricted to mono colored targets
Darkbolt - Exploits Nightfall mechanic. Cheap removal.
Backlash - Not only denies your opponent the spell it also damages them. that give us access to building tempo.
Can be replaced with Unseal or Corrupt
You may add
Lightning Storm -- filler spell. Its for those times when you find yourself in a target rich environment.
Can be replaced with Crystallize

Attachments
Permafrost - Can stop your enemy units on their feet, however it doesn't stop their abilities.
Winter's Grasp Nightfall trigger. Stun is sustained at night only
Lethrai Falchion Damage plus sustain combines well with Unseen Agent and Skywalk Enforcer

Units
Twilight Raptor - solid 2/2 one drop flyer
Darkveil Agent - Nightfall trigger, gives aegis
Unseen Agent - Nightfall trigger, puts a clock on your opponent
Miris Nightshade - Good damage becomes better when you have a curse active. 2nd ability is a Nightfall trigger that adds +1 to the Nightfall damage
Skywalk Enforcer - flyer that gets bigger every time you play a curse. Plays well with Zelia, the Vain ability.
Rindra, the Duskblade - Nightfall trigger, Damage plus sustain. She is your 5/5 beat stick
Zelia, the Vain - Very versatile, Drops early at turn 4, 2nd ability is quite handy.

I would welcome comments and suggestions to further improve this type of deck. e.g. sideboard
IGN: Quadgunner+8185 add me please!