Klaus is a man of average height and build, with short brown hair. When not wearing the standard Scout Regiment uniform, his attire consisted of a button-up shirt and dark pants.
Klaus seems to be a very straightforward man. While discussing Grisha Jaeger's past, Klaus expresses doubts at Grisha's loyalties, sarcastically noting that Grisha should have helped the scouts more if he truly supported them. He displays this trait again when the scouts begin fighting each other over meat, noting that it was a bad idea to have riled them up with good food.
Klaus is seen attending a meeting with Erwin Smith and the rest of the Scout Regiment's officers to discuss the recent revelations about Eren Jaeger's father Grisha. He expresses his disappointment since Grisha could have helped them out a bit more. As the officers depart the meeting in high spirits, Erwin informs them he will leave the teams up to them with Klaus reflecting they should keep the task a secret.
Later on he is seen eating with his fellow leaders as fighting breaks among the scouts over the meat that is being served in celebration for their next mission.
As the scouts prepare to depart for Wall Maria, they are met with unexpected fanfare from the citizens of Trost. Although his fellow officers are annoyed at the commotion, Klaus is left perplexed, wondering aloud whether the scouts have ever received such fanfare. They are all silenced by Erwin, who begins cheering as well and orders the Scout Regiment to begin its mission to reclaim Wall Maria.