No one said Karok was a giant. Just a giant-esque person. Like a sumo wrestler - the fat. So more like a body builder.
Nexon has... many times.
Chakun the Shaman entered the hide tent just after Karok was born. His mother Berdai, the Chief’s wife, was panting and red-faced. The newborn was crying in her arms, one of the few times in his life that he would be allowed to be so undisciplined. His father Hassan looked on as the Shaman took his first born child in his arms.
“15 pounds.†Chakun estimated, examining the baby's body for any flaws that would cause it to be cast over the cliff.
“Small.†Hassan grunted, looking disappointed. “He will be weak.â€
[skip]
12 humans were staked out in the sun, captives from the latest foolish attack on the tribe by a local village. They were dying by inches as the hot sun baked the life out of them. Chakun saw the six-year old Karok sitting cross-legged in front of one of the humans.
“What are you doing?†Chakun asked as he folded his nine-foot frame down next to the boy. Like Karok, Chakun was small for one of the Raven tribe at barely 450 pounds.
“Studying them,†Karok said. “They’re so much like us, except so small.â€
[skip]
“The war-leaders say you fought well despite…†the shaman trailed off.
“Despite my size?†Karok said. At seven feet tall and 400 pounds, the Shaman knew Karok had reached his full growth. He would always be the smallest among them.
[skip]
source: http://vindictus.nexon.net/News/Content.aspx?boardNo=100&contentNo=00CAr&pageIndex=6
I could have pulled sources where they literally call him a "giant", but to avoid confusion with him being called a "giant" for his relative size compared to Lann, Fiona, and Evie, I bolded the description his own people gave him in relation to his size/weight (as well as the shaman, Chakun, since they were both "small", although Karok is much smaller).