Odin always knew that there would come a day when he would become Rudra's right hand man.
He knew it from the day that he sent Rudra's soul back in Omega and gave him a chance at reincarnation.
Back then, him becoming the supreme lord was only a small probability, however, defying all odds Rudra did reach the summit and established a working relationship with Odin.
Although Odin was sworn to the perfect warrior as his soulmancer he felt no loyalty or fielty towards that man but rather felt only a strong desire to knock him down from his pedestal anyway possible.
Odin judged that the perfect warrior was currently suffering from the effects of karmic backlash and even if he did help Rudra beyond the conventional means, there was nothing that the perfect warrior could do about it as he could surely not afford to meddle in the controlled universe again in such a short timespan.