Graves doesn't know this when he begins pursuing a physical relationship with Credence. The witch he'd had a one-night-stand with all those years ago had never contacted him again, certainly never told him she was pregnant.
/Grindelwald/, on the other hand, DOES know. And while he's wearing Graves' face he at some point reveals it to Credence in the most horrific way possible. Probably tortures Graves with it too while he's being held captive.
What would be especially interesting would be to see how the real Graves and Credence deal with each other post Grindelwald's capture. The both of them trying so hard to act like a proper father and son should but just under the surface they're both drowning in how desperately they still want each other. How long before the dam breaks?
Graves/Credence, Graves is Credence's biological father
/Grindelwald/, on the other hand, DOES know. And while he's wearing Graves' face he at some point reveals it to Credence in the most horrific way possible. Probably tortures Graves with it too while he's being held captive.
What would be especially interesting would be to see how the real Graves and Credence deal with each other post Grindelwald's capture. The both of them trying so hard to act like a proper father and son should but just under the surface they're both drowning in how desperately they still want each other. How long before the dam breaks?