Seer!Frank
Frank Longbottom is a Seer, he doesn't display it as other Seers do and he's not really powerful enough to garner much attention which suits him just fine.
He mostly Sees things about his own future - harmless little things like where he finds a library book or a lost item, those close to him usually look to him when they want to know the weather.
The makes it serious and, after the third time he saved his team from a Death Eater ambush or found a survivor that even spells could not detect, he's dubbed Lucky.
It's only after Voldemort is gone, the Potters dead, that Frank has the strongest vision of his life.
In a week, Frank Sees, He will all but orphan his son when Death Eaters torture him and his wife into insanity.
It'd be so easy to avoid, just don't come out of hiding. Or move into a different house.
But....
Bellatrix will be free if not for this, He also Sees. And her rage will grow, boiling over when his son is eleven and she attacks while they're at Diagon Alley - killing Neville.
Which he can also avoid easily, only...
Frank keeps Seeing, over and over Neville dies at the hand of Bellatrix if she isn't arrested for torturing him and his wife.
The thing is, Frank and Alice love their son enough that they'd gladly face torture and the following insanity if it meant that Neville could grow up.
