All the special Khri use Utility except Eliminate which uses Debil and the Finesse vs Reflex stat contest. Calm and Vanish are mostly useful in PvP while I find Eliminate to be useful in PvP and PvE. They will all be useful to you at your current level, too.
Personally I'd recommend getting Eliminate since it adds a good amount of damage to BS in a lot of situations. I'd grab Elusion, too. It's hard to run with other Khri at low levels but the Evasion and Brawling boost is useful, and it's part of the Spar combo that buffs both thrown weapon skills. I like the Spar combo a lot since it buffs all weapons (except Slings), Backstab, and Evasion, so it gives both an offensive and defensive buff.
