Blackthorn

Love interest for Andromeda, father of Tempest, Dahliah, and Nebula (Colors are TBD)

Love interest, father

Male

Originally Fallen Tree

Slightly taller than Shining Armor

Light and dark blue

Cutie Mark; might be covered by his cape

Stands slightly taller than average stallion height

purple maybe?

Unicorn

Dazzling blue

Sidepart mohawk

Grounded but playful

ESFP

Blackthorn was trained to guard the village where Star Swirl and the other wizards made their home. Eventually he offered to personally guard the sisters, and grew very fond of Andromeda. The two were wed, and had three foals together.
During the Dragon War, he ran to safety with the three foals, following a group of Crystal Ponies all the way back to their home as they were pursued by an injured King Sombra, who still managed to separate Blackthorn from the others and do damage to him.
He lost his daughter C) Nebula in the Frozen North and had to journey on, eventually finding a community of yaks. They took him in but were unable to attend to his injuries, and he died there.

When Luna and Celestia became the official princesses of Equestria, they formed the royal guard in honor of his memory.

High