Started out as a very enthusiastic kid for learning magic. He was eager to live up to his mother's expectations and would perform excellently in his academic studies. Not knowing everyone very much, he started forming shallow friendships that didn't last except for one--- his roommate and cousin, Karl von Fritz.
Straight A++ student. Selectively friendly only to those who would prove beneficial to his academic career. Became bestfriends with his cousin towards the end in the middle of the year.
Some family issues arise on this year, he began to grow tired of his overachiever status. He started to actively join Karl's pranking spree and most would not suspect him. Grew out of his selfish box and would adapt a more charming attitude to reach a bigger circle of friends. Towards the end of the year, academic performance dwindled.
Rebellious phase. Karl successfully convinced him to imitate the look of a certain member from a Muggle boy band. His tattoos were temporary and would disappear after a few weeks so he changes tattoos every month or so. Started working out to achieve similar body build with said Muggle idol. Would roll down his sleeves within Hogwarts castle premises except for his room. Became more active in pranking but not to the point of meriting detention. Most professors and fellow students got surprised by his sudden change. Performed average academically throughout the year.
Got tired of styling his hair every morning and applying tattoos every now and then, Welner joined the "hobo sapiens" league. Would go to class without fixing himself. He would focus on expanding his circle of acquaintances and have fun rather than his academic duties. Although he might be neglectful of his academic assignments, he was open to learning more magic outside what is being taught at Hogwarts(He learns the spell Deletrius at this point.)
During vacation, his mom found out about his misadventures and forces him to change. He came back with a neater haircut and his academic performance would improve slightly. Still torn between pursuing a mediocre life or living up to family expectations.
Some events on his sixth year would convince him to change in a positive manner. Not anymore afraid of responsibilities, Welner would embrace his talent and rise up again in the academic ladder. Also joins the Ravenclaw Quidditch team, just to experience being a Quidditch player at least for the last year in school.