Malygos was a Villain who wanted to eradicate Magic. He was just like the Primalists at the time of his demise.
Infact the Dragons were following their Function due to Order Magic according to the Uldorus Report.
Malygos became like the Primalists due to Nether Dragon Disorder Magics releasing him from his purpose.
Since he had become a Primalist in mind the chances of him not siding with them upon resurrection is low.