"Who are you? And my--" Kaladin cut off, then sighed. "Kai... I thought I told you to stay at the village."

The wolf's blue eyes glowed, "Hurry father and your friend and father are in danger."
Kai slunk out of the bush, Like I'm going to let you have an adventure alone.

Kaladin sighed. "Fine. You're here now. But hurry!"

Kai came out of the bushes, I'm not letting you have an adventure alone and who were you talking to?

"I'm still not sure..." Kaladin admitted.

(Is he a Stromcaller? A Telekinetic maybe?)

(No to both. Look at the clues again)

Kai looks around and sniffs the air, Come on I smell Douglas, Haken, Kai looks up at Kaladin, and Selkie!

(Let me see:
-Mobian grey wolf
-Blue glowing eyes
-Appearently knew Douglas and Haken were in danger
-Abruptly appeared out of nowhere
A ghost, maybe?)

Kaladin quickly picked up the pace.

(Nearly there detective keep putting the pieces together)

Kai leads the way.

Douglas pants as he helps Haken carry Selkie, "Keep going I can catch my breath later."

(He also knew:
-Douglas' name
-Kaladin is Haken's son
So IF this wolf is indeed a spirit, that means he must have been either stalking them or (the more fun option) is somehow related to one of them. Judging by the fact he's not an echidna suggests that he probably mever knew Haken (due to the species' isolation), so he probably knew Douglas at some point instead. And since this spirit is a wolf, there is a chance that he is a blood realative to Douglas. And IF that's the case, that narrows things down to a few options.

-His father (Possible, as he has certianally died of old age by now.)
-One of his many siblings (Unlikely. It never mentioned that one had died)
-His son (Most likely, as he was the only one explicitly confirmed to be dead and was already brought up several times.)

And welcome to my brain.)

(Accually Douglas did mention only he and Skipper were left out of the ten siblings and rule out the first option and narrow it down even more detective.)