The Undead that were promoted to captain changed in appearance.
Bud increased in size, his shoulders grew broader and his height increased. The hunched-over simian look of the ghoul was gone. Now he stood tall, straight and powerful, with a noble bearing.
Spark grew a head-full of --skull-full rather-- of living crimson flames. His robes transformed from dirty, worn-looking castoffs to a richer more refined and elegant design.
Dog the dullahan now emitted a dark aura of dread and his armor was heavier and more gothic looking.