I'm giving this to Bane. True Bane doesn't normally deal with magic, but he deals with metas and powerful people all the time. Even without prep he's cunning enough, smart enough, and skilled to put them down, or at least give them a run for their money. Bane with prep is a whole new level. I believe that Bane is skilled enough to prepare and calculate what Harry's magic can do and find away to bypass it and break his spine. Would it be easy? Ah no, but I think Bane could find and use enough resources to take this. Plus he has the experience and willpower to keep him going. Voting for Bane. Plus I like him more ;)
Since he has prep, Bane will know how deadly Harry can be and will assume he is very versatile. He would use distractions such as flash grenades, henchmen and other equipment to distract Harry then attack when he is off his guard. He'd use his equipment and stuff to hit Harry first, Bane ain't stupid. He would use the environment to his advantage as well. Basically what I'm trying to say is that Bane wouldn't let Harry hit him with any spell, especially one as incapacitating as Levicorpus, cause if he did, its a GG. Bane would know exactly what to use and what to prepare for so that Harry would have a hard time getting that one hit.
Yeah I’m going with Bane. Both have totally different experiences but atleast Bane has dealt with supernatural powers before, whereas Harry would be totally stuck when he’s flashed and then dominated at a close quarter fight. Then Bane essentially bashes him up easily and wins.
Harry himself has summonables and since Harry wants to kill Bane (as per SBA) he may use Septumsempra as he did against Draco and Snape, most of all against Snape as he used it against him knowing what it would do.
Sever forever is a non-contact Spell too, like totalis, there is no beam to dodge or ball of light, it just cuts its targets into ribbons.