Secondary professions for a Dervish

Dervish Warrior
Armor-boosting skills in the Tactics skills make good additions for fragile Dervishes. "Victory is Mine!" works well with condition-causing Dervish skills.

Wild Blow is also very useful, as it's drawbacks are easy to avoid and critical hits are more powerful with a Sycthe.

Dervish Ranger
This profession combination provides little benefit for a Dervish primary.

Dervish Elementalist
This profession combination provides little benefit for a Dervish primary.

Dervish Mesmer
Signet of Midnight coupled with Sand Shards causes repeated, heavy damage. Epidemic can be used to spread conditions caused by scythe skills.

Channeling, a cheap and long lasting enchantment, and Mysticism provide ample energy for combat casting builds.

Dervish Monk
Mysticism with Protection spells grant massive amounts of energy back from cheap protective enchantments; However, Dervishes already have several self-healing skills that surpass the healing prayers line.

When not using Avatar of Melandru a dervish can deal with conditions using Mending Touch.

Dervish Necromancer
Like any melee character, the Dervish could use Plague Touch.

Tainted Flesh or Poisoned Heart (when combined with any enchantment ending skill) can spread conditions easily.

Dervish Assassin

 * Shadow stepping Skills such as Shadow Walk are useful to teleport up to casters in the back lines.
 * Shadowy Burden's snaring and armor reduction effects combine well with Vow of Strength.
 * Dash can be used as a no-attribute speed boost.

Dervish Ritualist

 * In PvP, Sight Beyond Sight is often used to counter blind long enough to spike an enemy.

Dervish Paragon
This profession combination provides little benefit for a Dervish primary.