Breakdown of Derjenige, der den Kommentar schreibt, liest auch den Beitrag.
auch
also, too
schreiben
to write
lesen
to read
der
who, which, that (relative pronoun; die, das)
Questions & Answers about Derjenige, der den Kommentar schreibt, liest auch den Beitrag.
Why do we use Derjenige here instead of just Er?
Derjenige means "the one" or "that person". It is used specifically to point forward to a relative clause that will define who you are talking about. While you could technically say Der, der..., Derjenige makes this forward-pointing relationship much clearer.
Why is Derjenige in the masculine form if we don't know the person's gender?
In German, the masculine form Derjenige is traditionally used as a generic "the one" or "he who" when referring to an unknown person in a general statement. If you were specifically talking about a woman, you would use Diejenige.
Why are there two commas, and why does liest come right after the second one?
The commas enclose the relative clause der den Kommentar schreibt. The entire block Derjenige, der den Kommentar schreibt acts as the subject of the main sentence. Since this entire block occupies position 1, the main verb liest must immediately follow it to stay in position 2.
Why do we use den for both Kommentar and Beitrag?