Guardian

If the Guardian is hit by an attack while the Bits remain alive, they will counterattack the party with a Shadow-elemental Delta Attack, and if one Bit remains alive, the counter will be single-target [verify]. The Bits will not do a Death Counter, so any attack that hits the entire screen but defeats the Bits is safe to use.

Once the Bits are defeated, the Guardian will attack the entire party with a Shadow-elemental Laser Spin, and then a Fire attack. After this it will revive the Bits and the cycle will repeat. The Guardian is vulnerable to all attacks and elements save Fire. Poor luck with Tech order notwithstanding, most players can defeat it in a single cycle.