Phobos is the Poison-elemental member of the trio. Its moves include Rainbow Wind, which blinds and silences a target while draining its HP, and Bio, a spell that causes Poison.
Similar to the Gargoyles, Triton, Nereid, and Phobos must be eliminated simultaneously and failure to do so will cause them to revive and retort with Delta Attack.
The battle can be won easily by using Odin. The Magic Lamp can even be recharged nearby.
Otherwise, the three can be easily defeated by repeated use of the Bard'sRequiem and multi-target attacks such as summons, though one should only use water, wind, or non-elemental attacks to ensure all three fall together.