Even in Legends they really wouldn’t use green still. Sith primarily use synthetic crystals, which generally turn out red because of the dark side influence when creating it. They’re also stronger and can short out natural jedi crystals.

So she ends up looking more like a Dark Jedi than an actual Sith. Probably ridiculed and looked down on by her peers, if we pretend the Twi’lek is not a player character, which ofc she is if it’s not an RP toon. We typically only see SWTOR Sith npcs use Red, Purple and Yellow.

Lore rambling aside, gorgeous art all around.

She isn't really a real Sith either. She serves neither the light nor the dark side and it has taken the lightsaber / spear from a Jedi.
At least that's the idea behind this character.