While on a mission Keith gets stung by a bug/plant and in the days following becomes more and more aggressive towards Lance
Lance was really confused about how Keith was acting, lately they had been getting along really well. But now every time Lance even so much as look in Keith’s direction Keith would glare daggers at him. During training one night Lance was sparing with Keith and was getting nervous Keith was actually going to hurt him. Keith ended up pinning him to the mat rather roughly, and warned Lance to watch his back. He shoved Lance farther into the mat one last time before getting up and leaving.
Days passed like that, Keith getting more and more aggressive, shooting threats and glares at Lance whenever they passed. But never once did Keith act any different towards the other Paladins. It was like he was normal one moment but as soon as he looked at Lance a dangerous look came across his face.
Lance finally decided to talk to Shiro about it after literally being thrown across the training room by Keith, however as he approached Shiros door he saw Keith leaning against the wall. Keith came over to him and harshly pushed him against he wall, leaning in close he spoke lowly into lances ear and told him if he said anything to Shiro he would kill him.