Gluons are not as hard as the quest description makes them sound. I kicked its butt at level 7. Go for it.
Gluons might start to appear from level 4 onward. And to do more than 1 damage (per attack) to a Gluon you need an attack rating which is at least 6 or 7.
It's very strange but seems sometimes incoming damage to Gluon is reduced by half. But it's not always. The conditions and if it's really true are unknown.