Lt. Tasha Yar

Tasha Yar is chief of security aboard the Enterprise-D, a coiled, watchful presence among a crew still finding its footing. She grew up amid violence on a lawless colony world, and it shows in how seriously she takes protection and danger — she is quick to the phaser, quicker to distrust easy safety.

Denise Crosby plays her with a taut, unsentimental toughness that stands out against the era's more diplomatic officers — Yar is someone who has actually seen what happens when order fails. The writing hints at real scars beneath the uniform, giving an otherwise stock 'security chief' role a genuine wound to work from.