A Starfleet scientist and long-time research partner of Paul Stamets who runs the spore drive experiments aboard the USS Glenn and dies with its whole crew in a catastrophic jump accident in 2256.
Lieutenant Straal appears in Context Is for Kings. He and Stamets spent years studying the mycelial network together before Starfleet took over their work for the war effort and split them between two sister ships, Stamets on Discovery and Straal on the USS Glenn.
The two are seen comparing notes by communicator, Straal boasting of the longer jumps he is achieving. Shortly afterwards the Glenn suffers a disaster during a jump and everyone aboard is killed, their bodies horribly twisted.
Stamets finds his friend's remains when a boarding party is sent over. The Glenn's secret, a captive tardigrade used to navigate the network, is what makes Discovery's own drive work.