The stranger from another reality soon enough heard tales of the infamous white-haired Witcher. He had to see for himself what all the fuss was about. It was easy enough to follow the man’s trail from the stories of others and the wandering god had magic at his disposal that did not adhere to the same laws. This realm was dangerous, yes, but so was he, and he could walk paths unheard and unseen.
When Loki found Geralt of Rivia, he did not make himself known for some time. Perhaps the man would sense a presence that refused to be revealed, keeping its distance. The god observed his behaviour; a few minor quests; his companions.
And then one day he waited for Geralt to venture out without Jaskier. It was the work of moments to steal in upon the unwitting bard’s room and enchant him. Jaskier would sleep for another day and night, and then he would wake and resume his usual activities without the memory of the Witcher - at least until the spell was broken.
Meanwhile, Loki took the form of the unfortunate Jaskier as well as his lute, and returned to the bar where he could await Geralt’s arrival. He sang songs - a little more expertly than the man whose face he had stolen - and charmed several of the locals. But he only had eyes for the Witcher once he strode back through the door.
“Ah! Geralt! Our dear Witcher returns! Come, come, fellow patrons, won’t you shower him with fortune?”