A quick search will show you that there is no one in the Marvel Comic Universe with the name of Grant Ward, but if you've been keeping up with Marvel's Agents of S.H.I.E.L.D., you know he is currently very important to S.H.I.E.L.D. and, just maybe, the larger cinematic universe.
Agents of S.H.I.E.L.D. writers have been smart enough to change their characters’ real names to avoid fans finding out their true identities before they needed to, as was the case with...
Mike Peterson (Deathlok) and Skye (Daisy Johnson).
With that in mind, could Grant Ward actually be a cover for another Marvel Comics personality (perhaps revitalizing a B-list villain) or a brand new character bringing Hydra back into the game?
Many fans have suggested the possibility of Ward being some version of Hellfire, Mr. X, or Taskmaster, but, in my mind, those theories are half-baked at best.
I'm here to offer some other suggestions as to who Grant Ward may be (if, indeed, he is someone else).
This one would be a stretch, but given the right set up (and change a few details), Ward could very well be the Ronin of Hydra. Trained by the KGB, Alexi became the Red Guardian, the Soviet Union’s version of Captain America. He was also married to Natasha Romanoff at one point. Now I know this doesn't fit with what we know about Grant Ward, but these details could be easily altered. Alexei later resurfaces as the assassin Ronin who is part of the Dark Ocean Society, where he recruits a young girl with illusion powers and outfitted a number of troopers with duplicate armor and powers of Vostok, Perun, and Crimson Dynamo. A man who creates a new version of himself and puts a team together? Something Grant Ward definitely is.
Count Otto Vermis was the area commander of a splinter group of Hydra, most well known as the Hydra agent that manipulated Jessica Drew into being their agent... Now this would be a great way to introduce Spider-Woman into the MCU as well! As Ward puts his version of Hydra together with von Strucker Jr., this would be a wonderful place to take us and it would be exploring a character that doesn't have much background.
Wolfgang von Strucker
I know He was killed in Age of Ultron, but couldn't Ward (and von Strucker's son) be filling a role Wolfgang himself once filled? Baron Strucker once formed a Hydra High Council consisting of Viper, a (new) Madame Hydra, the Kraken (a.k.a. Daniel Whithall) and Hive. Having close ties to the Secret Warriors directly before his comic death, this could very well be the direction Grant Ward is headed.
My prediction is that, without the movie rights to Viper, (presumably) Madame Hydra, and Gorgon, this is the direction that Grant Ward will be headed; creating a new version of the heads of Hydra, Grant Ward will serve as a viable and terrifying version of one of the new heads of Hydra.