Kruge

Kruge is a Klingon Defense Force officer who tried to take the secrets of Project Genesis for the Empire. During a fight with Admiral James T. Kirk on the rapidly-disintegrating Genesis Planet, Kruge is knocked over the side of a cliff and appears to fall into a pool of molten lava. 

However, before he hits the pool, he crosses through the intervening 96 years of time via a spatial anomaly formed by Genesis' collapse (the so-called "Fountain of Possibilities") and reappears in the Main Engineering compartment of the USS Jacqueline Dorsey. (Harry Potter and the Fountain of Possibilities: "Investigation")

Arrangements between the Federation and the Klingon Empire are soon made for Kruge to be transported to Qo'noS by the IKS Gorkon, accompanied by the Jacqueline Dorsey and the USS Enterprise (NCC-1701-A). (Harry Potter and the Fountain of Possibilities: "The Fire Inside")