The world was changing. The mortals learned. They worshiped him, because they did not understand him; before the foundation of their cult, he cared not for the opinion of mortals, but now he felt it... Their belief gave him power. He also sensed other beings at work in the land - some weaker than he, some as powerful as he, and some even more strong. However, he was different. He was no God - he had not been born in this side of the creation, and he did not recognize their over god as his own creator - merely a being who rescued him inadvertently when help was needed most. He was different than them in that he was bound to this land; while he could see the spiritual beings and, to a point, interact with them without spending any energy, he walked the earth as a material creature, and he knew that his children had no connection at all to the other side.
He contemplated the mortals for many years. They were... Puny. Weak. Yet he felt something towards them. They worshiped him, made him stronger - it seemed fair that he would do the same towards them. They also vaguely reminded him of his children - simple-minded, yet full of potential. Because of these reasons, he decided to assist them... And through them, strengthen himself.
His first action was to gather as many humans as he could who already worshiped him. He simply called them throughout the land, using his power, and waited for them to come. When enough had gathered to surround him, he gave them a mission - to walk throughout the lands of the south, spreading the word that, three years from now, in the heart of winter, the Wanderer would banish the snows from these lands forever.
And, three years later, on the foretold date, he honored his promise. Gathering a good part of his strength, he swept away the cold with all his might, forcing it to return to the poles, and installed a permanent border around the lands of the southern humans, making sure that winter would never return to these lands. Once that was done, all that was left to do for him was to resume his wandering, watch, and wait.
Spend an act to gather as many of my worshipers as possible, and send them throughout the southern parts of the human continent to spread the story that the Wander will, in three years during the heart of winter, banish the cold from these lands forever.
Three years later, accomplish the prophecy - sweep away the snows and the cold winds, sending them back to the poles, and install a barrier to prevent them returning, creating an eternal summer in the lands of the southern humans and spending one ice act.