.hack // G.U. Vol. 2: Reminisce Tips
When characters are killed and juggled by even more strikes after death, the game protects them from being hit again by removing their regular hit detection. However, this removal code is incapable of recognizing that a character has been revived from death unless it was from the ghost state. Therefore, if a character has positive HP after the death protection kicks in but before becoming a ghost, they'll get up, the protection won't be removed and the character will effectively be invincible. Using Rig Saem first and impaling yourself on The One Sin's laser is a nearly foolproof method of snagging this abominable shield.