Joshua Kain certainly has a unique job description, though possibly one badly suited to the Duelling League.
It turns out that he was such a bad mechanic that he broke everything that he fixed; So, he just hired himself out as a Wrecker to demolish machines.
While this was somewhat useful as a talent in his home world, where rabid robots run amuck across the world, it's not especially useful in the Duelling League; There are very few robots in Light. He does know some weak gravity and wind techniques, but ultimately, his Laconian Maces do most of his fighting, here.
Sadly, his maces haven't even gotten much of a chance to fight: his very first match was against Nina Wyndia the Second, in one of the most infamous runs to date,ending in Heavy. Fourteen seasons later, Kain got another unfortunate berth, being defeated by the dragon Bleu. Needless to say, the Wrecker's luck with League seems to be as bad as his luck with machines.