Background for Oath of Conquest.

[Mortheim]

Greetings! Wanted to ask for some help :3

I'm going to play (fallen) Aasimar Paladin in the next campaign. We start at 3rd level.
Stats: 16-8-14-12-8-16 (2 ASIs in charisma to get sweet 20).
It will be sword-and-board guy with dueling fighting style.
"The Prince" will be base for his personal code and he will be the ideal ruler according to it (though not sure if I will be able to roleplay it 100% accurate) with Lawful Evil alignment.

Because I build my characters around personality, i already have problems with choosing background:
1) what my paladin was before? I really like "Folk Hero" and "Inheritor" background. Both nicely fit into his character;
2) taking Folk Here makes it easy to tie fall of aassimar to "defining event" is somewhat easy - he stood against terrible monster. And he "fell" the moment his Guide left him alone. Wanted to take some baddy (maybe even devil or demon) from Mordenkainen's that could be frightened. Or maybe there might be better idea? Deal with the devil?
3) taking "Inheritor" background is risky knowing my DM: if there will be tattoos then they might be a map, which will lead to some treasure like Holy Avenger, and, at the same time, spell that will destroy the world - though there is a huge chance that DM will allow me to choose what type of inheritance I have;
4) another reason to take Folk Hero is proficiency with artisan's tools - i really like possibilities introduced with Xanathar's guide;
5) for Inheritor gaming set is nice to use in social encounters, while music instrument might be cool to show the "nobleness" of this aasimar;
6) another point for Folk Hero is animal handling and land vehicles - i will have glorious steed in two levels :3

[Avigor]

Greetings! Wanted to ask for some help :3

I'm going to play (fallen) Aasimar Paladin in the next campaign. We start at 3rd level.
Stats: 16-8-14-12-8-16 (2 ASIs in charisma to get sweet 20).
It will be sword-and-board guy with dueling fighting style.
"The Prince" will be base for his personal code and he will be the ideal ruler according to it (though not sure if I will be able to roleplay it 100% accurate) with Lawful Evil alignment.

Because I build my characters around personality, i already have problems with choosing background:
1) what my paladin was before? I really like "Folk Hero" and "Inheritor" background. Both nicely fit into his character;
2) taking Folk Here makes it easy to tie fall of aassimar to "defining event" is somewhat easy - he stood against terrible monster. And he "fell" the moment his Guide left him alone. Wanted to take some baddy (maybe even devil or demon) from Mordenkainen's that could be frightened. Or maybe there might be better idea? Deal with the devil?
3) taking "Inheritor" background is risky knowing my DM: if there will be tattoos then they might be a map, which will lead to some treasure like Holy Avenger, and, at the same time, spell that will destroy the world - though there is a huge chance that DM will allow me to choose what type of inheritance I have;
4) another reason to take Folk Hero is proficiency with artisan's tools - i really like possibilities introduced with Xanathar's guide;
5) for Inheritor gaming set is nice to use in social encounters, while music instrument might be cool to show the "nobleness" of this aasimar;
6) another point for Folk Hero is animal handling and land vehicles - i will have glorious steed in two levels :3

Ultimately, any background can work with any personality traits. I normally use traits from multiple backgrounds, browsing through all the published backgrounds to figure out what works for me; granted, if your DM won't let you customize at all, then yeah that could be a problem. My advice below isn't taking the traits themselves into account, only the general feel of the backgrounds.

You're going with a Prince style LE Paladin? Part of me really wants to knee-jerk to Acolyte, Caravan Specialist (http://dndadventurersleague.org/wp-content/uploads/2015/04/Mulmaster-Bonds-and-Backgrounds.pdf), City Watch, Knight (either the Noble variant or -of the Order from SCAG), Noble (Normal or Waterdhavian), Soldier, or Trade Sheriff (http://dndadventurersleague.org/wp-content/uploads/2015/07/Hillsfar-Regional-Character-Options.pdf) to explain the archetype's general attitude that others will obey him; Folk Hero doesn't strike me as quite matching this unless you modify it from personally standing up for the people to rallying an entire rebellion, and Inheritor IMO feels a bit too close to a Hermit in most respects. OTOH, a map that leads to a Holy Avenger that's serving as a key holding some seal or other in place (think the Master Sword in OoT) would be fun...

I hope you figure something fun out!