Apollo first posted the video you see reuploaded
here on twitter.
This conversation ensues.
Apollo then deletes the video above.
DarkViper uploads
this video to explain his side of the story.
Apollo replies with
this video.
DarkViper calls him out for cutting his explanation in
this video.
TLDW
Apollo publicly shames DarkViper on Twitter for not paying an editor.
DarkViper explains in a video his difficulties with the editor, how he didn't complete his contract since he did his work in a very shoddy manner and calling Apollo out for not asking his side of the story before publishing the video.
Apollo then posts a video where he selectively chose content from DarkViper's video in order to put shade on him, DOXXing the editor at the same time.
DarkViper calls him out for cutting his clips and not being honest in the video.
EDIT
Making it clear that DarkViper
clearly said in one of the videos above how he pays on a "by-contract" nature.
You don't complete a "contract", you don't get paid for it.
EDIT 2
You may want to read EZScape's tweet as well.
Many other figures known in speedrunning like Kosmicd, GFC, KZFrew, Joshimuz, Xem, Jrose11 and Nathaniel Brandy replied to this tweet about the Apollo situation.