There are times where Eobard wonders how Barry's spindly frame hasn't snapped in two under the weight of all the guilt he carries on his shoulders.
(It's too delicious a thought - the picture of Barry twisted and broken at his feet, utterly sundered, powerless, and looking up at him with those eyes that never fail to say too much - the idea makes that dark recess Eobard calls a heart crackle with a sensation that's almost but not quite as intoxicating as the Speed Force.)
But Barry can't be broken. Not yet. Eobard still needs him intact, on his feet, pushing forward as far and as fast as his blind faith will take him. He'll get around to demolishing Barry Allen, in time; Eobard's waited too long and made too many plans for it to go any other way.
In the meanwhile, he puts on his best Harrison Wells and rolls sedately after Barry, transmogrifying his bottomless hate and envy into paternal concern and every word he says comes from the blackest pit of him ("heart"), telling the Flash that he is stronger than this, that he can overcome anything, that not every single bad thing in this world is his fault.
Eobard's lied to Barry for so long, but these truths have never been part of the game. These things will always be pressed onto Barry with a frank and ruthless honesty, the kind that obviously makes Barry ill at ease to accept.
(The idea that the Harrison Wells believes in him without reservation is almost too large a concept for even Barry's lighting-quick brain to absorb. And there's the lie - Harrison Wells has been rotting in the ground for two decades, hasn't he.)
Guilt is a thing Eobard recognizes as never having actually felt, himself. He can do - has done, will do - bad things for good reasons just as easily as he does the reverse, justifying every lie, every murder, every patient smile, every unwavering vote of confidence.
Eobard has a plan, and seeing Barry crumble before the time is right has never been a part of that plan.
(Seeing him crumble always has been. The moment Barry Allen looks at him and sees Eobard Thawne for the first time - well. Eobard gets a jolt of electricity down his spine that Harrison Wells has no business feeling.)
So he does what he can to shore Barry Allen up. To drag some of the Flash's doubt and guilt and sadness off those delicate shoulders and swallow them into the void where Eobard disposes of such things.
Little by little, Barry Allen becomes the man Eobard Thawne always wanted him to (feared he could) be.
Little by little, Eobard Thawne becomes the man Barry Allen always thought he was.
Not enough to ruin him, not enough to prevent an orchestrated lifetime from playing out exactly as he's designed. Still, it's far later in the game than he'd like when he finally realizes the cost of letting the Flash into his -
(heart)?