i seem to be missing something, why is the anakin run mostly done with obi-wan? is it because it counts as beating the game with anakin if you just play the last level as him or is there a skip or...?

Yes, since the only objective is to beat the game with Anakin, only playing the final level is enough. There is skip that has to start with Obi-Wan, since it does not work otherwise. The playthrough starts from a new savefile and when performing said skip, every level and the Master mode for Anakin will be unlocked afterwards, so the game counts it as a real play-through as well. If you are interested how it works, take a look at this TAS: At about 9 minutes you see the skip, an explanation can be found in the comments at said timestamp (or ask me if something is unclear).

Note that this is no longer the case, what was called "Any% Anakin" when this forum post was made is now just "Any%" and "All Levels - Anakin" exists to encompass the majority of the Anakin game. I locked the thread since it could create some confusion.