Enderal: Forgotten Stories (Special Edition)

In Enderal the combination of certain different Skilltrees can result in a synergy.

To quote directly from the SureAI's Website:

"From level 19+ on, the two disciplines with the highest number of AND a minimum of 10 Memory Points invested into each of their Memory Trees will unlock a special class, granting bonuses to some of your stats and skills, as well as certain special effects. Only one special class can be active at a time, and putting more Memory Points into a third discipline can change the active special class."

The following synergies exist:

Arcane Archer (Any mage discipline + Trickster)

Assassin (Blade Dancer + Infiltrator)

Battlemage (Elementalism + Vandal or Keeper)

Black Mage (Elementalism + Sinistrope)

Blade Master (Blade Dancer + Vandal)

Brute (Blade Dancer + Lycanthrope)

Dark Keeper (Sinistrope + Keeper)

Drifter (Vagrant + Lycanthrope)

Druid (Elementalist + Lycanthrope)

Ghost Blade (Infiltrator or Trickster + Phasmalist)

Ravager (Sinistrope + Lycanthrope)

Scourge of the Woods (Thaumaturge + Lycanthrope)

Seraph (Thaumaturge + Keeper or Vandal)

Shadow Dancer (Sinistrope + Infiltrator)

Spectral Warrior (Blade Dancer or Vandal + Phasmalist)

Spektralist (Sinistrope + Phasmalist)

Soulcaller (Lycanthrope + Phasmalist)

Swashbuckler (Vagrant + Trickster)

Throat Ripper (Infiltrator + Lycanthrope)

Simply skill accordingly and you shall receive the achievement as soon as you hit Lv 20