That is certainly a conundrum. Looking at the official definition, you have "in which". The only usage in-game is a reference to a place of battle "in which" Arnvid "suffered a mortal wound". It is referring to a location. I actually dispute that "in which" is a conjunction. It's actually modifying a noun "The place in which". That being said, in-game doesn't use "kolos" as a question word -- only "wo" (who) does this.
Now, if you wanted to limit your usage of "kolos" to what you see in-game, try following this logic: Ask "Where are you?". You can use kolos in this way -- "Talk about the place in which you are / stand." "Tinvaak do golt (place) kolos (in which) hi los / kriist (are/stand)." Now, maybe you shorten it to "Golt kolos hi los/kriist?" which may not be "a complete sentence", but it is a phrase that describes your desire to know where someone is. You can shorten it further to, say, "Hin golt?" ("your place" -- I've seen someone use this phrase), but I still use "Kolos los hi?" because in meaning, it conveys "(implied place) in which you are?" due to the definition of "kolos".
You can make your own decisions, but ultimately the person (or dragon) you're talk to needs to share at least some understanding of the words you're using.
Certainly in English "In which you are?" doesn't communicate my desire to know where you are (sounds nonsensical), but we use "where" anyways. Kolos as "in which" can't because with anything other than location. It's only that in English we use "in which" to mean "where" most times. Other languages might have their own phrases for this. We are forced to look at Dovahzul usage in-game or as stated in official sources, like the referenced PrimaGames guide.
Here is a reference for how English uses "where" and "in which" https://www.quickanddirtytips.com/education/grammar/where-versus-in-which If you notice, they're interchangeable, but only as the