Integra And Synth. The Fusio Twins

So just came up with this idea from re reading Symbiopony and also loving fusions in anime and other shows. Integra(inn teh gra) and Synth are twin beings created by Celestia and Luna's parents as their assisstants and bodyguards. The whole family got along well but when their parents left, The two looked to the twins as siblings. Sadly, during the attack of Nightmare Moon, the twins were made to suffer by her wrath. Synth was sealed in a mirror and couldn't leave. Angered Integra bonded his power to Celestia to help her fight Nightmare Moon. In the final moments of the battle she was forced out of Celestia and trapped in a gem which forcibly gave his power to any who wielded it. This gem would become the heart of the Alicorn Amulet. One day, Twilight and her friends come to the castle and find the mirror of Synth in a secret room. Due to his curse he can only leave by linking with someone to hold himself outside the mirror. However, it would take discord to remove Integra from the gem. The twins are actually very different. Synth is a very cautious overprotective brother while Integra is still very trusting and more open to making freinds. Synth is a tall, strong unicorn with his mane and tail bieng grey and silver while the fur is gunmetal gray. Synth is a Pegasus with Ghostly white hair and Prussian blue body