Since Transmutation allows the user to give the user's Aera properties of substances or objects, Michael crafted this technique by giving his Aera the properties of both weapons and wings. To activate this technique Michael needs to clasp his hands together in front of his chest, similar to a prayer, and the ten Sephiroth Arms appear behind him. The wings vary in size, but they somewhat resemble large white feathers. Since he also can give commands to a wing to switch to weapon form and to switch back to wing form, it is also a Manipulation technique. He is also capable of turning them into cannons that shoot light Blasts, similar to Aera Channellers.
This technique mainly allows the user two things: to fly and to use the wings as weapons. To use the weapon, he detaches it from his back and the weapon. He generally uses one or two arming swords as his main weapons, but he is also able to use other types by fusing his wings. Since the blades are made of solidified Aera, they are incredibly powerful, being capable of cutting a weapon made of steel in half rather easily. Weapons that have been somehow enhanced by Aera are able to resist this effect for longer.
However, due to the incredible power of this technique and the fact that Michael is using Manipulation, the category he has the lowest affinity to, the Sephiroth Arms have several self-imposed limitations. The most important one: Michael cannot kill anyone using this technique, and the added stipulation that if he violetes this limiation, he will die. Other limiation is that he can fly the best with all ten wings, but if he detaches one to use a weapon, his ability to fly becomes more clumsy. If he detaches too many, he won't be able to fly at all.
Michael has also created a total of ten sub-techniques while using this technique.