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This is just a general comment but rape isn't really something that people foreground in roleplaying games right now. Wizards largely dropped the half-orc apparently because they felt that it necessarily involved abuse; which was yucky and not really something that ought to be in a game for kids.
When half-x are retained in modern setting they are usually presented as a sort of separate culture. Eberron has the Khorvaire (half-elves with their own racial identity) and the racially blended human/orc/half-orc culture of the Shadow Marches.
A cue was taken from them in the development of the setting, the Imperium half-elves are Temperavir (you can see the
little blurb about them); a sort of bureaucratic middle class that help the Imperium function. (You can think about India where I am under the impress something similar happened during the colonial period during british rule)
Of course their powerful eladrin patrons frequently maintain families of half-elven associates and servants, partially so that any children that result from their dalliances can easily be "fostered off". (which is appalling on the social level; and is part of the moral ambiguity present in the Imperium).
Again that doesn't mean that violent behavior doesn't happen in the Imperium; it means that it's (and it's close relation coercive behavior) is so common there's actually a system in place for it.
But all of this sort of ignores a fundamental question... why do you want your character to have this sort of background? What sort of story are you trying to tell?
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Personally I would suggest being "from the Imperium" if you want to be from the Imperium.
However half-elves who are fostered with Temperavir families are quite common in the Imperium; so that wouldn't really make your character unusual. Since it's so common most children aren't looked down upon. At least that was my intent in the original setting, but the current writeup of the Imperium doesn't get into those sorts of details.
So you'd potentially have chances to interact with your parent under social circumstances from a young age (if they were interested in keeping tabs on you) or you'd have no idea who they were (and your foster parents may have no idea, depending on who your eladrin parent was).
If you were here to meet him clandestinely after years of search you could easily be looking to meet the same person that Amicus (a PC I'm considering playing) was here to meet (a grizzled old Eladrin paladin).
Of course a traditional paladin wouldn't take advantage of someone, let alone violently, so that may or may not work in the story you want to tell.
If you're looking for a father who is more of a traditional "green-tights in the woods" type character then a typical Eladrin from the Elvin Court would make more sense. Of course... if your father just appeared, attacked your mother and then left... you have realistically, very little chance of ever finding him.
Also...
And this is just a personal thing...
My interest, as a DM, in running a story about this sort of thing is pretty low (i.e. near zero).
I don't, personally, tend to run games that go in that direction; I introduced it as an element in the Imperium because the eladrin were there and ruling over humans in very close circumstances so it sort of fit (half-elves should have a place in the setting as a race I thought...) but I tried to work hard to keep it as small and non-yucky as possible.
The majority of Temperavir are just born to other Temperavir who were born to Temperavir; they have eladrin somewhere up there the same way that most Americans are originally from somewhere else, but its not necessarily important to a given individuals identity.
So you may find it difficult to really explore this whole thing in a game; in the sense that DMs may not be interested in bringing it up.
