What if Lucius had died in the first war?
There seems to be a general consensus that Draco got most of his poor traits from his father and most of his good traits from his mother. So I wonder, what would have happened had Lucius been killed in the prior to 1981 and Draco had been raised solely by Narcissa?
Narcissa is fiercely loyal, especially towards her family, especially towards her son. She would (and does!) protect him at all costs as we see in both HBP and DH. So imagine how she would have reacted had she not had the (sometimes conflicting) loyalty to her husband or at least no reason to follow his idol.
Because had Lucius died in the first war, killed in action in a raid or something, the Dark Lord would have most likely brushed his sacrifice off saying something like he was not strong enough. After her husband’s death and that disrespect, Narcissa would most definitely have turned on the Dark Lord. Even if she still hated muggleborns, even if she still believed in pureblood supremacy, you can bet that she would be against the Dark Lord. When Bellatrix’s ideals were a threat to Draco’s life, Narcissa threatened her right back and hexed her for being in the way. If she would turn on family, just think what she would do to the man who took her husband away from her.
She would have gone straight to the Order of the Phoenix, plying her way with all the information she had learned from Lucius, all the tidbits she had overheard while eavesdropping in her own home. Imagine Sirius’ shock when he walks into the Order meeting and finds he ex-cousin (re-cousin?) sitting primly on Dumbledore’s right hand bouncing baby Draco on her knee, the Black mask of indifference firmly set on her face. That meeting runs long. Narcissa has more information about the Death Eaters organization than the Dark Lord ever intended anyone to have, especially an unMarked woman. Safe houses, hierarchies, inner circle members, spies, double agents, dark creatures who have been bullied or enticed into fighting, corrupted Ministry employees, intended targets, she tells them everything. But only after acquiring the vow of every single person in the room that they will protect her and Draco. She forces Dumbledore to make an Unbreakable Vow.
She had skillfully rid the Manor of the Dark Lord–an apparently weak woman, openly mourning her husband is poor company–but she still knows well enough to act meek when Death Eaters come by the Manor. They continue to drop hints at tea, make pointed insinuations at dinners and introduce her to the ‘particular friends’ at the occasional ball she deigns to attend. Through this, she maintains the Order’s dependence on her, feeding them each bit of information she gets; new targets (the Potters go into hiding), new members (Wormtail is outed before he has opportunity to do harm), relocated safe houses (after the the Hogsmeade location raid student recruitment for the Death Eaters dropped dramatically).
Regulus comes to the Manor one afternoon on the pretense of a family dinner and tells her that he knows she is the one feeding the Order information. She has her wand digging into his throat before he can say “Bludger”. Instead of threatening her, he begs her to take him with her; he has crucial information about how to defeat the Dark Lord. At the next meeting, Sirius walks in and chokes on air when he sees his brother sitting on Narcissa’s right playing peek-a-boo with Draco.
Draco and Harry are not enemies at Hogwarts. They meet as toddlers at Sirius’ post war celebration. Narcissa allows the friendship because while Lily might be a muggleborn, she was also instrumental in the Dark Lord’s death and besides, James is a pureblood, even if his line has always been rather liberal. Harry isn’t scared off when the Sorting Hat tells him that he would do well in Slytherin because even though Ron said, “there’s not a witch or wizard that went bad that wasn’t in Slytherin,” Harry knows that Reg and Cissy (”Regulus and Narcissa, Harry, please. I don’t care what Sirius says, he’s an idiot!”) were in Slytherin House and they’re both heros. Draco isn’t surrounded by poisonous frienemies or bulking lackeys because his longtime friend Harry is there with him and when some of the other Slytherins prove less than kind, Harry and Draco leave them in the dirt (quite literally, maybe Uncle Moony shouldn’t have taught them that spell so young) and find worthy friends from other houses. The Dark Lord doesn’t return, most everyone lives and all because Narcissa does revenge better than anyone.