Multi-time Tetris champion Jonas Neubauer has passed away. Known for his incredible skill in the puzzler, Neubauer was a key factor in a recent surge in Tetris interest, stemming from his captivating championship performances, and regular Twitch streams.

The news was delivered via Neubauer’s personal Twitter this week. “It’s with a heavy heart that we deliver the terrible news that Jonas has passed away from a sudden medical emergency,” the tweet says. “He was the absolute best. We are devastated, overwhelmed with grief, and we already miss him dearly.” He passed on January 4, and was 39 years old.

Jonas was the inaugural Classic Tetris World Champion in 2010, and would go on to win the tournament six more times over the course of eleven years. In 2018, his losing effort in the finals against Joseph Saelee drew widespread attention on Twitch, leading to a renewed interest in Tetris and the surrounding competitive scene. Neubauer was a long-time Tetris pro, recording himself achieving high scores on VHS, and sending them to friends to be uploaded on old messageboards back in the early noughties. He was included as a subject of the Tetris documentary Ecstasy of Order: The Tetris Masters, the making of which spurred the original CTWC.