SuStel:

So what I said is true... when you're dealing with verbs that don't take objects. If the verb does
allow an object, then the "doers" of the verb, whether the subject or object, can do the verb to each other.

Thank you for explaining this; as soon as I read the {Qo'noS tuqmey
muvchuqmoH qeylIS} I was about to ask about it.

However, reading the canon sentences, I noted something else which
seems a little strange:

muptaHvIS tay''eghmoH QeHDaj Hoch
All his rage focused in one blow  (PB)

If I was to translate the original klingon sentence, then I would
write "while he was striking, all of his anger made itself together".
But since we have the {tay'}, then shouldn't there be two subjects (at
least) which would be/made together ?

Let's remove the extraneous material. tay' QeH the anger is together. This is apparently a valid meaning of tay'; it doesn't require multiple subjects that are together. You can think of it as anger consisting of multiple parts, which have been gathered into one.

Note that I would never understand tay' QeH standing all on its own; it's a metaphor that only makes sense in context. Don't take this example to mean that Klingons consider anger to consist of multiple parts. This is only a metaphor in a poem.

-- 
SuStel
http://trimboli.name