Saleen had been planning for quite a long time. He knew that everything he did and said would have been scrutinized by the goddess. As such, he had only used his usual level of powers in battles, instead of amplifying them using his magic amplifiers.
It was not until he faced the goddess that Saleen put his true powers to use, finally showing off just how powerful he could be when he used his magic amplifier.
He had been hiding his powers the whole time just to make the goddess misjudge his power level.
The fire dragon conjured by the Scorching Candle continued to throw fireballs, which he had infused with ball lightning and lightning icicles.
All six godly items had fixed spells in them. The goddess was plunged into the sea of magic. While she was extremely adept at manipulating elemental powers, the six godly items did not rely on ambient elemental powers for spell-casting. Elemental creatures stored by Saleen powered the spells instead.