Appearance and Profile
Shaciel is tall and thin with an appearance similar to that of a humanoid and is slightly larger then a standard Evangelion model. The body proportions of Sachiel do not match that of a human as Sachiel has no neck, large and broad shoulders, thin arms that reach below its knees, and is feet are elongated. Sachiel's core is contained in the middle of its body and is slightly protected on the sides by a simple rib cage. Large portion's of its body are covered in bone and its face has a beak much like a bird. Sachiel is also capable of regenerating parts of its body as it regenerated its face after being struck with a N2 mine.
Sachiel's respiration system, unlike the other angels, is located in Sachiel's thighs and crotch as a set of gills on each thigh and a pair of nostrils in the crotch. The said gills can also double as a propulsion system when under water. One of Sachiel's natural weapons are the lance like bones in each of the angel's arms that can become energized. After regeneration, Sachiel gained the ability to fire energy blasts that form crucifix-shaped energy spikes. Sachiel can also use its own AT field as a boost for its jumping ability and can also change body shape and muscle mass along with being able to self-destruct if at a loss.
History
Sachiel is first seen in Neon Genesis Evangelion swimming through the flooded ruins east of Tokyo-3 before emerging and being engaged by the JSSDF who attempt to stop the angel. The JSSDF are unsuccessful at damaging the angel or slowing its advance. The JSSDF manage to knock back Sachiel with a missile barrage from their VTOL crafts but Sachiel soon adjusts to the attacks and presses forward. Sachiel also shoots down on VTOL craft instead of doing a counter attack and then uses its AT Field to leap away from the attacking craft. The only attack of the JSSDF that successfully slows down Sachiel by luring it to the Mt. Takanosu region and detonating an N2 mine under the angel, which manages to force the angel to regenerate and gives NERV enough time to prepare Evangelion Unit-01.
After reaching Tokyo-3, Sachiel becomes more violent with its attacks by sending out long range energy attacks before stumbling upon Unit-01 after wondering for a bit. As at the time Shinji Ikari had no experience piloting an Evangelion before, Unit-01 falls on its face giving Sachiel the upper hand allowing it break Unit-01's left arm, impaling one of Unit-01's eyes, and flinging it against a building. After a period of silence, Unit-01 reactivates and goes berserk and proceeds to rip a part of Sachiel's newer face off and charges at the angel again before being stopped by its AT Field. Unit-01 proceeds to regenerate its broken arm and tear through Sachiel's AT Field but is stopped by an energy attack from Sachiel, which fails to stop Unit-01. Unit-01 proceeds to break both of Sachiel's arms and kicks it into a building before charging again. Then Unit-01 breaks off one of the angel's few ribs and uses it as a means to break the angel's core, but Sachiel realized it was at its end so it wrapped itself around Unit-01 and self destructed. After the explosion, Unit-01 walked away from the explosion with only moderate damage.
Information from Sachiel is sourced from the Evangelion Fandom Wiki.