So, i decided to do a Sparks guide because, i didn't find so many!
Sparks is a medic, but not any type of medic, shes a sniper medic. She can snipe teammates across the map and revive them or send out deadly charges of electricity to her enemies, shes haves 80 health, so lookout for the 1 shooting potentials. (Fletchers stickies,Katanas, etc.) but with that health, she comes with a 470 speed ratio, that means shes one of the fastest mercs in the whole game (the other one being Aura.).
Since Sparks is a medic, you need to keep an eye out for your allies health, and also revive them when possibile, always stick behind them, if you're more experienced, then you can go lone hunting. But i don't sugest doing that.
Sparks comes from the pool of the pistols (that means her primaries are machine pistols and her secondaries are normal pistols) for the primary slot she has the options of the: Empire -9, MP400 and Tolen MP. I find the Empire - 9 the better since it's like an Hochfir but with less magazine size and also lower damage. the MP400 is also pretty good, it has the highest damage than the others. The Tolen MP has more damage than the Empire, it's basicly the MP400 and the Empire mixed together. And for her secondary slot she has the options of the: M9 , Caulden and Sebstalt .7 . All of them are pretty nice, but you're gonna use them when you need to reload your primary.
General Loadouts and Augments
Sparks haves 1 augment only for her, and that's Quick Charge (basicly it makes your revive gun charge faster.) the augments you might wanna search are: Get up, Potent Packs and Quick Charge. The best loadouts (in my opinion) are: 383 Companion Agent ; 342 Service Agent ; 241 Service Agent ; 273 Technical Agent ; 181 Technical Agent and the 143 Service Agent.
Sparks only has 2 abilities (like every other medic except Phoenix.) :
Revive Gun : Fires high concentrated electric shocks, it firstly has to charge and then release it to fire, a half charged shot does 30 damage to the body, a half charged shot does 60 damage to the head. A fully charged shot does 60 damage to the body, a fully charged shot does 120 damage to the head. Also don't let it charge so much if not it's gonna overheat.
Med packs (7 Seconds) : Sparks throws out small med packs that heal anyone who touches them, a picked up health pack gives 30 health, a direct hitted health pack gives 40 health, with potent packs a picked up health pack gives 35 health and a direct hitted one gives 45 health.
Sparks' main weapon isn't the machine pistol, but it's the revive gun, try landing as many shots as possible, and in the mean time revive allies, keep the medpacks, don't waste them on the ground, heal allies that desperatly need health, don't waste them if they are missing like 20 HP, Sparks' main job is to revive, not to heal. always try keeping 2 medpacks for yourself, if not you might die. Sparks technically has unlimited health and ammo, try staying in the backlines and try landing as many shots as possibile with the revive gun. In a situation when you're caught by suprise, don't wait till you fully charged the Revive gun, just grab your machine pistol and try killing the enemy, then heal up when done.
(So yah this was my guide on how 2 Sparks. I hope it might help <-<;)