Ok, here's how to verify the integrity of the rar archive and repair it if necessary.

First of all, download every part of the DeedV2.0 rar archive and at least DeEd.MKV.par2.part01.rar. Extract Deed2.par2 from said rar file to the same folder.

Get Multipar from http://hp.vector.co.jp/authors/VA021385/ and install it. Once it's finished right click on Deed2.par2, select "Open with..." and choose Multipar. It needs a few minutes for the process the finish, but in the end the program window should look like this:

If instead it says that some blocks are lost, you need to download further parts of the DeEd.MKV.par2 rar archive. You do not need to get all par2 files, it's sufficient to just download the same number of slices as those damaged. When looking at the file names in the above screenshot, f.e. +003 means that said par2 file contains three additional slices.

As a last step extract the par2 files, repeat the above steps and once checking is complete, simply click on "Repair" and wait for it to finish.