Critique My Character Idea?

I’ve been in a solo campaign for a one shot to start off my experience with D&D but I feel like that doesn’t really assist me in making a group friendly character. So here’s my story and lore for my character and I want brutal honesty so I can make some appropriate tweaks so that this character is ready for the right campaign. 

Levi Mercy is an Avariel from a small Skyland city that is apart of a holy clan of Clerics, priests, and paladins under a single deity, Justitia, that’s only worshipped by them. My character is a kind yet naive person that’s lived her sheltered in the temple. Being raised in a holy environment she’s very diligent and disciplined but she’s also faced some hate from her own clan. This is because her mother, a high priestess of their deity, gave birth to Levi but has markings of a different deity as markings.  These markings were quickly hidden by her mother as Levi wears a blindfold from then on or is hidden from the public mostly and only gets to go out when her paladin father comes from his crusades. She’s basically looked down on by those that know of her markings. Mainly raised by her father when he’s home and by the general temple members.

She tries to stay positive but has a poor self image and came to idolize her father and want to be like him based on the stories he’d share. She becomes a paladin and trains under her father and finally is old enough to do her Rite of Passage as a Mercy Clan member and get first hand experience in the real world outside of her city. Now she’s feels very strongly about Justice but because of her upbringing and the way she was treated she’s very open minded and understanding of the grey areas of good and bad. She’s believes everyone is initially good so she gives everyone the benefit of the doubt and trust too easily.

This is where the problem of my character arises. I wanted her story to be that her mother and father were possessed by deities the night my character was conceived through a rare but dangerous practice. This practice creates a mortal being that can also gain access to divine realms or outer planes mentally over time as she levels up as a paladin. I start it at level 5, but with each level after that she gains more markings that are a combination of Justitia’s and the other deity. My idea was for the other deity to be Selune but I’m not sure how that will be taken since they are both women and I don’t know much about if Selune ever had a lover and how deities reproduce in D&D lore.

Now this is main character Syndrome territory but the draw back of being this rarely historically documented being is the large drawbacks. Ancient long forgotten deities good or bad get a vessel into the material mortal world through her. She’s like a beacon to those with ill intent so she attracts dark entities to her and the more divine power she gets the greater the enemies trying to claim her body or energy. She needs to develop a more structured and balanced mind to fend off the dark entities that feed off her insecurities or suffering. They do this to break down her defenses and get a step closer to claiming her as a vessel. I don’t know if having her do random saving throws to see if she gets affected by the whispers of evil in her ear that cause to her to break a mental defense is a possibility. Maybe the mental barriers are parallel to her level so starting at level 5 she has 5 barriers that get tested? No clue how to work this without getting others opinions. It’s not fully fleshed out because I saw she was becoming a main character type problem and just want to know how to fix this or change things without losing the core factors or if this idea is just complete crap and I should scrap this. I’m sure this is probably a lot of work to implement into a campaign so maybe someone can make it simpler or explain how much actually work would need to be put in for this character to work.

I will say my character gives me a combo of Giselle from Enchanted, Raven from Teen titans with the vessel/needing concentration and discipline to keep things stable and Hercules with his naive, innocent and sincere behavior. Her wanting to prove herself and not feeling like she belongs but trying to be a person worthy of love and respect so she can be with her deity parents who truly see her is another thing she can work towards. 

So give me your honest thoughts. Thank you!

Okay yea the being born from two different gods is pretty nutty all things considered. That would probably bear something like an Empyrean, which is an extremely high level thing to deal with. It depends on your dm, but gods can reproduce from practically anything in mythology, see Loki's many children, how Athena came out of Zeus’s head and stuff. The best way to place it at a lower level is making the gods themselves weaker, maybe the gods involved are only worshipped within a small region or are demigods.

For the main character syndrome, the only way to deal with it is to rely on the rest of the party. Have the character learn from their party members, maturing or becoming worse depending on how their allies act. You probably shouldn’t deal with the random saving throws, that just places way too much attention on your character and away from the others.

For a relatively new player, and especially one who doesn't have a long history with their group, I would absolutely avoid making your character the child of one God, never mind two! That's the kind of thing which is very much Main Character Syndrome, and a lot of people will see it as such no matter how you see it.

One of my characters apparently left an impression of Main Character Syndrome on another PC based - as far as I can tell - on nothing more than the way I flavored my first casting of a cantrip.

Now, I don't know what an Avariel is, but it sounds maybe similar to an Aasimar. You can absolutely have your PC and her parents be Aasimar and still have your celestial markings. Just maybe don't go for "child of two gods" as your second character. The DM would presumably expect that you want that heritage to factor into the campaign, and such a significant one would carry a lot of story "gravity".

It started off fine, but then . . . this has "Chosen One" vibes all over it. 

Some of this is great. A naive person who grew up in a small isolated religious community making their way in the strange and confusion world-at-large. I played a character just like that for a full campaign - a light cleric who grew up on an island occupied by a small religious community dedicated to keeping the lighthouse burning 24/7. The campaign was basically his Rumspringa. It was wonderful!  Through a character like that you get to experience the world around you like a child exploring things for the first time. And it gives you a chance to be the voice of reason and calm when others want to go all Murderhobo. 

That's all you need. You don't need to be the actual child of deities. That's just gratuitous. Just be a person. A person who is clearly different from other people, not because they are an actual Godchild, but because they grew up in a wildly different setting and they don't fully understand the world they're adventuring in. Ask the DM about the general demographics of the campaign setting. Just playing an aasimar in a region mostly populated by humans could be enough of a difference to stand out and attract attention, both good and bad.

That's all. Just play an aasimar paladin. Trying to force a "I Am The Child Of The Gods" storyline on the table will just perturb the other players. It's just a bit much. You don't have to be a god to be special. Every character is special, not because of who their parents are, but because of who is playing them.

My first suggestion would be to file away all the backstory details. If you aren't in a campaign yet, how do you know what gods the campaign world will have? Or whether avariel even exist as a species/subspecies (they don't in 5e, so that's already going to have to be homebrew)? Or even what level you'll be starting at? There are too many specific details here that won't fit in many/most campaigns

Instead, focus on the kind of character you're interested in playing in terms of personality, etc. Things like this:

She tries to stay positive but has a poor self image and came to idolize her father and want to be like him based on the stories he’d share. She becomes a paladin and trains under her father

Now she’s feels very strongly about Justice but because of her upbringing and the way she was treated she’s very open minded and understanding of the grey areas of good and bad. She’s believes everyone is initially good so she gives everyone the benefit of the doubt and trust too easily.

...are a great starting point. You have a young paladin, sheltered and idealistic and maybe a bit naive but trying to be what she thinks is pragmatic (creating some potential conflict points with your oath or your order for the DM to play with), who's trying to live up to her father's legacy but fears she'll fail and is unworthy of that legacy

That's already plenty to work with. The whole "secretly a child of multiple gods" thing... in the end, that's going to be completely up to your DM, not you. You can suggest reasons for why she was treated badly as a child and feels so distant from her mother, and maybe the DM will decide to incorporate some of that into the campaign, or maybe they'll surprise you with something completely different that fits their world better. You especially shouldn't be trying to add brand new mechanics to the character to represent her succumbing to evil, or whatever, without your DM's input. Those can be role-playing choices anyway. You don't need saving throws to justify having your character listen to intrusive thoughts once in a while

All that said, if you're really committed to the 'god-markings that multiply as she gains power but also faces corruption' thing, there's actually a solid third-party subclass for that in 5e which might be getting a 5e24 update at some point -- the Runechild sorcerer from the Tal'Dorei Reborn book. As a Charisma caster, sorcerer makes for a fairly friendly multiclass with paladin, if you want to go down that road with the character later on and have the markings be more than just flavor -- which would also be a perfectly valid choice

I agree with the above, both being the child of gods and having the potential to randomly become corrupted by something evil can be very very disruptive to the rest of the group. Only after you have played for at least a year with a group of friends would I ever consider having any kind of character that might betray the party. The other thing you are missing is a strong drive for why this character is going out to adventure by themselves and can't go home to ask for help, and why do they need friends to help them?

The key aspects for a D&D party member are:

1) Why does the character need to work with the rest of the party? Your party might be beggars, thieves, soldiers, smugglers, unstable mages, immature, impulsive, potty-mouthed, etc.. Why is your character willing to overlook the flaws of the rest of the party to work together?

2) Why does the character want/need to risk their lives going for adventures? The adventures might be honourable but they might simply be killing monsters for money. Why would your character dive into a mine to kill a bunch of spiders?

3) What does the character need to learn to become a better person during their adventures? Are they lacking confidence, or are they self-destructive, or are they greedy, etc... 

What I would keep from your current backstory are:

Levi Mercy is an [insert species here] from a small city that is apart of a holy clan of Clerics, priests, and paladins under a single deity. My character is a kind yet naive person (Great this is a hook for her future development) that’s lived her sheltered in the temple (also great, this gives a reason she need other people's help who have more worldly experience).

This is because her mother, a high priestess of their deity, gave birth to Levi but has markings of a different deity as markings (this is good for the DM to have other NPCs remark on / interact with your character, and could be a mystery that is entangled with the main plot of the campaign). She’s basically looked down on by those that know of her markings.

 She tries to stay positive but has a poor self image (Another good opportunity for the character to grow) and came to idolize her father and want to be like him based on the stories he’d share (this is another opportunity for the DM to challenge your character, maybe the stories are true but maybe some aren't..). She becomes a paladin and trains under her father.

Now she’s feels very strongly about Justice but because of her upbringing and the way she was treated she’s very open minded and understanding of the grey areas of good and bad. She’s believes everyone is initially good so she gives everyone the benefit of the doubt and trust too easily (great, another opportunity to grow!).

She’s like a beacon to those with ill intent so she attracts dark entities to her (this could work as the reason she is going out adventuring or why she is looking for friends / a party, she has become a danger to her city/family, and she need to find someone / something to protect herself from these entities) 

To be brutally honest, my first thought on reading this "oh man, it's another of those backstories". Frankly, this reads like the elevator pitch for someone's Next Big YA Protag- special relatively isolated community, two very significant parents, some kind of inherent stigma to leave them socially isolated, naivety, and then a big twist of having some super special but dangerous power. As people have said, the parentage and powers are really overkill and generally not a vibe other players or the DM will like to see in a D&D character. The bit about being ostracized is also somewhat at odds with an open and trusting demeanor. As a rule the former tends to create some degree of wariness or at least worldliness about the nature of people in general.

Note that I'm saying "one of those backstories" as someone who's done it several times, and then looked back later and regretted it.

Speaking personally, I find "naive" to be a mild flag as well- it can give a vibe that you're going to deliberately make disruptive choices because "it's what [the character] would do", and even if you're just looking for player engagement not everyone is up pulling another character back from the edge as a recurring point. That part is admittedly more personal feelings than objective critique, but imo it'd be a good idea to talk the concept out with the group and go over your intentions vs what will work for the others.

I'd say just start with a basic "earnest Lawful Good Paladin" chassis, some non-world-shaking details to give the backstory color, and ask the DM what kind of player hooks they're looking for and flesh out something appropriate. If they're looking to build personalized arcs for each character, you can revisit some of your bigger ideas, if they're just looking for a group of adventurers to clear dungeons and fight a classic BBEG then it's best to leave the grand destiny backstory for another campaign/character.