Keegen

The bird queen, air elemental, most underappreciated frame - Zephyr!

Release date: 2014-02-05

Passive: Striking from the skies above, Zephyr is significantly lighter in comparison to other Warframes, dramatically altering her airborne physics. While airborne, Zephyr’s equipped weapons gain a 150% Critical Chance bonus.
Tail Wind - From the ground, charge and release to launch Zephyr into an airborne hover. From the air, tap to dash forward, or aim down to dive bomb enemies below.
Airburst - Launch a burst of massively dense air. Hold to send enemies flying, tap to pull them toward the burst. Damage increases per enemy hit.
Turbulence - Creates a wind shield around Zephyr, redirecting all incoming projectiles.
Tornado - Create deadly tornadoes that seek out and engulf enemies. Tornadoes deal the elemental damage type they absorb the most. Shoot enemies engulfed in Tornadoes to do additional damage.

Acquisition: Zephyr’s blueprints can be researched from the Tenno Lab in the dojo.

The invisible marksman, legal wall hack, one shot many kills - Cyte-09!

Passive: Gains Practiced Aim when he kills an enemy by damaging their Weak Points, increasing his Critical Chance against weak points by 1% up to a maximum of 300%, lasting for the entirety of a mission.
Seek - Plant an antenna that projects a forward wave scan. Detected enemies take increased Weak Point Damage, and become visible through walls. Weapons gain Punch through.
Resupply - Throw two Elemental Ammo Packs that instantly refill the active weapon's magazine, while granting the weapon an additional instance of the selected Elemental Damage and Status Effect. Reload clears the effect. Sniper Rifles gain extra damage.
Evade - Jump backwards and become invisible for a short duration. Killing enemies on their Weak Points extends the duration and heals Cyte-09.
Neutralize - Summon the Neutralizer, Cyte-09's exalted Sniper Rifle. Bullets ricochet off Weak Points to seek out other nearby Weak Points. Alt fire lobs a Cold grenade that completely freezes enemies.

Acquisition: Main blueprint is acquired upon completion of The Hex quest. Component blueprints are acquired from Höllvania Central Mall Bounties as an uncommon drop. Alternatively Cyte-09's blueprints can be purchased from Amir of The Hex.

The stormbringer, a walking conduit, running around at the speed of sound - Volt!

Release date: 2012-10-25

Passive: Traveling along the ground between2 Volt's attacks will build up static energy, adding bonus Electricity damage toward Volt's next weapon attack or ability cast.
Shock - Launches a shocking projectile. It stuns and deals high damage to a single target and chains damage to nearby enemies.
Speed - Volt energizes his body and nearby Warframes, giving them increased speed and dexterity for a short time.
Electric Shield - Volt deploys an obstacle of energy, providing cover in any situation.
Discharge - Paralyze nearby hostiles with a damaging electric charge, this also shocks approaching enemies.

Acquisition: All blueprints can be acquired from the Tenno Lab in the dojo.

Master of magnetism, most attractive frame, magnets - how do they work? - Mag

Release date: 2012-10-25

Passive: Mag automatically Vacuums Pickups that are within 8 meters towards her (does not stack with the other Vacuum effects. DE WHY!)
Pull - Mag stuns enemies as she manifests a magnetic vortex. The vortex pulls in Polarize Shards and stunned enemies to place them directly in front of her.
Magnetize - (TAP) Enclose a target in a magnetic field that ensnares nearby enemies and deals damage over time. The field pulls Polarize Shards that orbited Mag and shrapnel into the deadly mix. (HOLD) Mag surrounds herself in a magnetic field that absorbs ranged attacks and reflects damage back in a destructive cone.
Polarize - Emit an energy pulse that depletes enemy shields and armor as it restores ally shields. Debris left over from the pulse becomes Polarize Shards. Nearby Polarize Shards orbit Mag and cut enemies, inflicting bleed status.
Crush - Magnetize the bones of nearby enemies, causing them to collapse upon themselves.

Acquisition: Main blueprint can be purchased from the Market. Component blueprints can be obtained from defeating The Sergeant on Iliad, Phobos.

The posterboy, master of the sword, the ol' reliable - Excalibur!

Release date: 2012-10-25

Passive: Excalibur has improved mastery in the Tenno art of the blade, receiving +10% Attack Speed and +10% damage bonuses for melee attacks while wielding swords, dual swords, nikanas and rapiers.
Slash Dash - Dash between enemies while slashing with the Exalted Blade.
Radial Blind - Emits a bright flash of light, blinding all enemies in a small radius for several seconds.
Radial Javelin - Launches javelins towards enemies, dealing high damage and impaling them to walls.
Exalted Blade - Summon a sword of pure light and immense power.

Acquisition: Available as one of the three starting Warframe options. Otherwise his main blueprint can be purchased from the Market, component blueprints can be obtained from defeating Lieutenant Lech Kril on War, Mars.