Mercy is a slow moving, medium damage, low health melee support hero, made highly mobile and efficient by her Q and Trait.

Trait: "In the Fray." Mercy gains 1-8% increased healing based on how many wounded or dead allies are near her. Does not count herself. Allies leave a Death Marker when they die, visible only to Mercy so she can better place herself to take advantage of her Trait.

Z: Just a normal mount.

Q: "Guardian Angel." Mercy quickly flies towards a targeted ally, latching on to them with her healing beam and restoring health until her arrival when she detaches the beam. The healing amount changes depending on how long it takes her to reach her ally, healing a maximum of 600 4% per level when used at max range. Low-Medium mana cost, 5 second cool down. "I've got you!"

W: "Caduceus Blaster." Mercy pulls out her blaster and fires one shot in a straight line, dealing 85 5% per level damage and slowing the first enemy hit. The third consecutive hit in a row on the same enemy will stun for 0.5 seconds instead of slow and charge Mercy's Heroic. High mana cost, 2 second cool down. "Am I gonna have to cap'a bitch?"

E: "Damage Boost." Mercy links herself with target ally or enemy within a short range, slowing them by 5% and boosting their physical damage by 15% and making her next use of "Caduceus Blaster" stun, even if it wasn't the third attack. The effect ends when Mercy cancels it, walks out of range, or breaks it with "Guardian Angel." Medium initial mana cost 1% per second it is active, 8 second cool down. "At least it will be quick."

Heroic: "Heroes Never Die." Mercy can target a Death Marker and resurrect target ally, bringing them back to life with 1% health and invulnerability and rooting them in place for 8 seconds while their health slowly recovers to full. target is unable to attack or cast spells while the invulnerability persists. High mana cost, cool down charges with healing done from the beginning of the game, and with "Caduceus Blaster" stuns. "Not on my watch."

Possible Talents:

Helden sterben nicht(Heroic) Allows Mercy to resurrect in a targeted AOE instead of just one ally, but removes their invulnerability while their health restores and they are rooted in place.

Caduceus Staff(E) Increases the range and pulls Mercy to her target when she engages "Damage Boost."

Angelic Arrival(Q) Mercy releases a burst of healing, centered on her, when she arrives at her target.

I'm just spit-balling with the numbers and names(and lore text) here, but I thought this was an interesting concept my friend and I came up with to differentiate her from Lt. Morales. Please let me know what you think! :)