The first "und" part is a Khalani particle for making a wish, kind of an optative mood or a kind of auxiliary morpheme. Here it is stating "I hope that...", it is followed by "lara khar", this means quite literally "with peace" (Notice that "khar" has already been stated as meaning "peace"). The thing is that the whole phrase literally means "May (you) be with peace", the pronoun is obviated here as the meaning is pretty straightforward from context.
This conjunction, lara, means "with, alongside, next to" and is very similar to other conjunctions in other languages such as Latin "apud". In this case the peace is wished to be "with" or to accompany the person to whom it is wished, and this is how Protoss normally say this expression "with peace", not using "at" as in English but rather "to be with a state of mind", to be "accompanied by peace".
In any case, the full sentence would be;
Und nas lara khar
May you be with peace, i.e. 'Be at peace'But you could also say, more grammatically;
Und laranas khar
May peace be with youNotice the subtle difference in meaning and the -nas ending which is the second person singular. All pronouns are appended this way to this particular conjunction. If we were to substitute it for the first person singular (I, me);
Und laranakh khar
May peace be with meHere the pronoun changes when it is attached to the conjunction, as the other sentence would have been;
Und ankh lara khar
May I be with peaceOf course the verb "to be" is obviated, since there is no such verb in Khalani, so it is understood from the particle "und". This is also applicable as a normal "with" conjunction, thus;
Ankh laranas, Nas laranakh
Me with you, you with meOr in a sentence;
Und taro laranakh var!
May you honor his name with me!This is all for today, next time we'll see some more pronouns!