Alright I've been lurking for awhile now and decided to sign up and start posting. On the subject of Thunder and Lightning has there been any reason given for them doing any of the things they've done outside of generic bad guy reasons like "Because were evil!" or "Were going to take over the world!" I've read a few things on the Kinnikuman wiki, this forum, and I can't read Japanese but I've been looking at the raw scans at mangahelpers and all I know is this much.
1. Travel back in time to after the tag arc of the original Kinnikuman series and screw with history by killing Robin Mask and prevent Kevin Mask from being born. Seems that Kevin not existing is the important part because Robin being saved by the time traveling new generation and Alisa tacking the hit instead is good enough for them. Plus they didn't try killing Robin again after that nor did they kill any of the other legends before moving on to...
2. The Choujin Tag Tournament trophy which they seem to want because it has some weird plant growing on the bottom of it that if you eat it or the seeds from it you get a huge power boost and/or magic healing powers.
Beyond that has there been any hints of any kind of what they hope to accomplish with all of this or does anyone have any kind of theory of any other goals they might have other than the obvious world conquest stuff?
Well, yes actually. In the early chapters, Thunder and Lightning said that they came back in time to steal the competition bulbs under the trophy (later learned with help from Neptuneman and Mammothman) and make themselves super powerful to create a world ruled by evil in the name of Satan.