A Nuker is defined as an E/Me that invests into Fire Magic and Energy Storage.
Nukers will use heavy-hitting spells, such as Firestorm, Meteor Shower, and
Rodgort’s Invocation, and combine these spells with Mesmer skills such as
Arcane Echo and Echo to reuse these skills in rapid succession.

Following the 11.10.05 update, this update made Nukers less useful because of
the fact that monsters now detect and flee from AoE-related spells. Even with
this update, Elementalists are still learning to adapt to these changes.