The thing you can see at the bottom was a character description I came across today.
I don't mind people creating a whole family tree for their characters as it makes the
character way more interesting and lively, but please don't make the whole royal cast of
MLP their parents/aunts/grandparents etc. It will just end up ridiculous and looking like
what you can see above.

A little further explaination of what is going on there:

First of, Twilight from the EqG dimension Married Flash Sentry (the pony version) and had
Cadance as a child. There's also this thing where King Sombra is Flash Sentry's brother.

Cadance was abandoned by her parents and then adopted by Princess Celestia as her nice.

Starlight Glimmer is the long-lost sister of Twilight and Shining that they have never been
told about and was presumed to be dead by their parents. In reality though she married Sunset
Shimmer (either the pony or EqG version, I don't care), after which they adopted a filly named
Melody Flamethrower.

Shining Armor and Cadance had a second secret child together with Flurry Heart that they
told nopony about because they were too embarassed how their son looked. They locked him away
until his 18th birthday and then kicked him out.

Melody Flamethrower, who looked ugly as fuck as well then proceeded to marry Amber Quartz (the
name he had given himself, since his parents didn't bother giving him one) and had a child that
is successfully relative to every single piece of shitty royalty in the MLP universe known to date.

Congratulations to whoever created the short character description. You spawned this abomination.
Now live with the guilt.