Deckard Cain by DoctorFoxman

Beyond Understanding (W): Horadric Cube deals double damage to non-Heroic enemies.

Tutor Arms (E): Cain's escort gains 15% Attack Speed.

Tutor Mind (E): Cain's escort gains 15% Spell Power.

Tome of Identify (Q): If cast on an area, Identify's range is increased by 50% and cooldown is decreased by 5 seconds.

Watchful Eye (Q): If cast on an enemy, Identify's duration is increased by 50% and enemy Heroes that enter their vision are also revealed for 3 seconds.

Equivalent Exchange (W): If Horadric Cube hits both an allied and an enemy Hero, refund its Mana and reduce its cooldown by 5 seconds.

Extra Bag Space (1): Increase the number of maximum active satchels to 5. Satchels heal 50% more Health and Mana.

Identify Path (Q): Identify increases the Movement Speed of Allied Heroes in its area by 15% for its duration.

Horadric Guard (E): Cain's Escort gains 20 Armor, reducing damage they take by 20%.

Swift Aide (E): Cain and his escort gain 20% Movement Speed.

Calldown: Haedrig (Active): Cooldown: 60 seconds
Activate to call down a Blacksmith that repairs Structures, one at a time, near target point for 40 seconds, healing for 100 Health every 1 second.

Arcane Power (W): Increase Horadric Cube's basic damage and healing by 50%.

Protected Escort (E): After not taking damage for 5 seconds, Cain's escort generates shields equal to 15% of their maximum Health over 3 seconds.

Empowered Escort (E): Cain's escort's Basic Ability cooldowns are reduced by 30%.

How did that get There? (1): Cain's Lost Satchel has global range.

Identify Weakness (Q): Enemy Heroes affected by Identify lose 15 Armor for its duration, taking 15% more damage.

Master Transmuter (W): Reduce Horadric Cube's delay by 33% and increase its radius by 50%.

Honorary Member (E): Protection of the Order applies to Cain's escort, giving them 50 Armor against Non-Heroic sources, reducing damage they take by 50%.

Inventory Full (1): Cain's Lost Satchel gains a second charge and its cooldown is reduced by 15 seconds.

Unwelcome Guest (R): Town Portal can now be cast on enemy Heroes. A Hero targeted is instantly teleported back to their Hall of Storms.

Hello My Friend! (R): Increase Stay Awhile and Listen's radius by 33%. Allied Heroes within range are healed for 500 (+4% per level) Health over Stay Awhile and Listen's duration.

Embrace the Unknown (W): Damage, healing, and effect duration of Basic Abilities used on Horadric Cube are doubled.

Help me! (Passive): When Cain dies, he is placed in a cage at the location of his death. Allied Heroes can try to release him for 15 seconds. If they do, Cain is revived instantly at that location with 50% of his maximum Health and Mana and the Hero that revives Cain counts as an additional escort until Cain dies. If they don't, Cain revives normally at the Hall of Storms. This effect has a 180 second Cooldown.

For more clarification, here are some examples and explanations for how Horadric Cube works.

Damage Added:
Muradin casts Storm Bolt, which deals 110 damage, at the Cube. The Cube eats the Bolt, hitting no other targets without its piercing talent. When the Cube explodes, it deals 120 + 110 damage in its area, equaling 230 damage.

Healing Added:
Malfurion casts Regrowth, which heals 150 Health and 465 Health over 15 seconds, on the Cube. The Cube eats the Regrowth. When the Cube explodes, it heals 120 + 150 Health in its area, equaling 270 healing.

Effects Added:
For the Muradin example, Storm Bolt also stuns for 1 second. When the Cube explodes, it will also stun all enemies in its area for 1 second. For the Malfurion example, Regrowth also applies 465 healing over 15 seconds. When the Cube explodes, that over time healing is also applied to all allies in its area.

Embrace the Unknown:
If Muradin's Storm Bolt is eaten by an EtU Cube, the Cube will explode for 120 + (110 x 2) damage, equaling 340 and stunning enemies for 2 seconds. If Malfurion's Regrowth is cast on an EtU Cube, the Cube will explode for 120 + (150 x 2) healing, equaling 420 and applying a 930 healing over 30 seconds to allies.

The Cube is only effected by Skillshot or targeted abilities, so AoE effects like Frozen Tempest and Entangling Roots aren't applied to the Cube.

The idea behind the Cube is to create a risk/reward system. Do you aim your skillshot to stun an enemy now, or add it to the Cube for a larger effect as long as they stay in range?

-Cain's Health and Basic Attack damage/speed are very low, comparable to Abathur's damage and Tracer or Junkrat's Health.
-Identify's area range is similar to Tassadar's Oracle.
-Horadric Cube's cast range and AoE are similar to Kael'thas's normal Flamestrike.
-Stay Awhile and Listen's radius is similar to Kael'thas's Phoenix.

This concept is reviewed and updated as frequently as feedback is given. Feedback is appreciated, numbers are subject to debate, and thanks for looking!