Ramiel becomes the first Angel to physically penetrate the Geofront when it's drill bit breaks through the armor before it's downfall during Operation Yashima. Also, since its appearance, other Angels that appeared after it ultimately began to taking more aggressive attempt to cause the Third Impact where they began to attack anything that stand in their way instead of ignoring them.
Ramiel is the very first Angel that began to take its aggression on any non-Evangelion beings instead of merely focused their agression on Evas alone: While it did share hostilities with any Angel-based entities like Evangelions where it immediately attack them on sight, Ramiel would also attacked other enemies includes artilleries, tanks, aircraft, etc. that dare to approach it.
Nevertheless, like all Angels, it focused on searching for Lilith the second Angel within GeoFront to cause Third Impact.
Ramiel has appearance of a gigantic floating crystalline octahedron (two pyramids attached at the base, one on top and one on bottom). The surface of Ramiel's armor is blue and highly reflective. Because of it's shape and the manner it moves, Ramiel does not appear to be "alive" in a conventional sense and is too much like floating war machine or UFO of some sort. Contrary to this, the Angel later revealed to be indeed biological: When it's remains was demolished later on, bloody red squares are seen where the Angel's armor/surface structure is being taken off, indicating that it does have blood.
This ultimately rectified on it's counterpart in Rebuild of Evangelion film series where it now portrayed as a shape-shifting entity that can changing its form to suit its attack or defense requirements (even includes sniping foes and deflecting any projectiles from very far distance!) as well as the ability to mold it's lower point into a more-organic looking drill contrast to it's Anime Series version that more like futuristic drill device. The creature even bleeds when attacked as well. Although, it's basic form when not engage any enemies is the classic octahedron form seen in the TV series.