One your character is Drow
2. your character is a caster
3. game focuses caster do to amount of damage you can put out which is also why Gale is focused, and if he's in your party Wyll is focused. It's standard tactics even on pnp, and first shooters. You drop the one able to the most damage first, forcing cleric/healer to focus on healing them. Last person you take out is the tank.