The novel does say that Kishiar is huge. So it can be both hahah.
huge in what way...
In all the ways that you're thinking lol
Minor spoiler because your comment reminded of it:
Kishiar himself admits this at one point. When Yuder wants to do it Kishiar's goes- I'm not blind, I know I'm big and you're injured so we're not doing it
This man is way too sweet. Best ML ever period
JustEmber is absolutely right in saying he's huge in all the ways, but height-wise, Kishiar is canonically 198cm which is almost 6' 6". The other character isn't a named one, so we don't know his height, but Yuder for example is 182cm which is 5' 11". They're all giants ╥﹏╥
The height difference between Kishiar and that cadet Dude’s a giant or the other guy is just small.