What happens with nick and adalind on Grimm?

In "Grimm," Nick Burkhardt and Adalind Schade have a tumultuous relationship that evolves over the series. Initially, Adalind is an antagonist, but as the story progresses, they develop a complicated bond, especially after she becomes a mother to Nick's child, Kelly. Their dynamic shifts from adversarial to cooperative as they face various threats together, but trust and conflict remain persistent themes in their interactions. Ultimately, their relationship is marked by both tension and a sense of shared responsibility for their daughter.