A question of character's uniqueness

I realised that some of my characters had a problem: they were too generic.

Here are some concepts

First, the ex-mercenary, Mike Borkoma.

Mike is sure nice looking, but there was something missing to him.

Until today (July 22th)

Bioluminescent tatoos.

But while in mission, he cover those with a special make up to avoid disconfort with his helmet'visor.

Daniel Alann Ram: you got vitiligo now
Vitiligo is a skin condition which makes white spot appear on the skin.
Daniel was already not a great fan of sun bath, so it does work already for him.
Adding a little characteristic makes him more easy to recongnize and will add something to the character.
But I have to make sure this is noticed by the new enconters he makes.

Those concept will be apply. I just need to remake the illustrations of both of them.