Stryker Malthus is an outcast from House Malthus of the Stormlands. Once his house had declared for House Baratheon of the Stormlands, Stryker had decided to swear loyalty to the Lannisters to the ire of his cousins and the rest of his family. He had led the Lannister army in the war of the five kings in the Battle of Oxcross and recently against Highgarden. His favorite pasttime is falconry. Stryker owns a sword named Slayer. In his downtime, he and his lieutenants Ryman and Bertholdt run a underground crime syndicate that deals in smuggling. 

Once he split from the main branch, he adopted a new banner for his house:

Old: 

New: