Kurt Darkholme is the alternate version of Main Marvel Universe (616) Nightcrawler. As such, he shares all the same alternate versions of that Nightcrawler.
Especially worth noting among Kurt Darkholme's alternate versions is the younger version of himself from another world named Kurt Waggoner. In addition to being a teleporting mutant, young Kurt Waggoner was also a robotics expert and physics prodigy. Although their time together was brief, Kurt Waggoner had a substantial impact on the older, world-hardened Kurt Darkholme. In fact, it was the young Kurt’s self-sacrifice to save the world that partially inspired Darkholme to give his life to do the same.