Israfel is the Seventh Angel. Its most notable aspect is perhaps its ability to divide into two distinct bodies, each with its own Core.
During its initial confrontation with Evangelion Unit-01 and Evangelion Unit-02, the Angel is severed in half by Asuka Langley Sohryu using a sonic glaive. While momentarily appearing defeated, the severed halves transform into two distinct bodies, catching Shinji and Asuka off guard. The resulting battle is short, leaving both Evangelion Units embedded head-first in the ground.
With NERV having failed, the U.N. Forces step in with Nē Weapons. At the cost of rearranging the landscape once again, approximately 30% of the Angel is successfully destroyed by the explosion. Unfortunately this only buys NERV time, as the Angel begins to regenerate.
Initial NERV estimates give them six days before Israfel fully regenerates, enough time to formulate a plan. Since the Angel has the ability to divide its Core into two distinct forms, even destroying one of those forms would allow it to simply merge and regenerate. In order to completely destroy it, a simultaneous attack on both its bodies would be necessary. To this end Shinji Ikari and Asuka Langley Sohryu spend an entire week training to coordinate their movements to a musical score.
After six days Israfel arrives at New Tokyo-3, and is once again faced with the two Evangelion Units. This battle however reveals that Israfel's most powerful aspect is perhaps its ability to learn and adapt. Using its incredible speed and agility, it would now parry or dodge most attacks, while using razor-sharp claws and long-range energy beam to attack.
Shinji and Asuka's coordinated efforts ultimately overcome Israfel's defenses, simultaneously assaulting and destroying both of its Cores. The entire battle lasts a mere 62 seconds.