Lionel Hawke is a NEXT with the ability to turn invisible. He first appeared as a fill in for Barnaby Brooks Jr., Bunny. He then made another appearance as the "backstage thief" which gave the 2nd season heroes a run for their money because no one was able to capture him. It wasn't until Wild Tiger gave him a good chase that he was captured, thanks to his running into a wall-- Rock Bison, that is. He is voiced by Ben Diskin in the English dub.
His power depends on how long he can hold his breath in. In Episode 14, it also showed that his power allowed him to turn anything he came into contact with invisible, as the bike he was attempting to escape on also vanished.