PROGENITOR-0, aka The Nexus Engine, is an artificial being constructed by the Cult of the Outward Path to serve as both an object of devotion and a means of channeling planar energy for their mad plans of transcending their mortal forms. It was designed by Acolyte Runath and built by Acolyte Kyan, both of whom believed that it would provide the Cult with the power they so desperately craved; as a result, its construction was a heavily-guarded secret, kept deep within the ancient stronghold of Riftstone Keep.
It is found in the Voidforge Workshops (Act I, Level 2), and it must be destroyed before access to the next level is granted. Additionally, players must find and destroy the Cult's notes on the machine's construction to progress to the final level of the Keep, where they must hunt down Acolyte Runath to prevent him from rebuilding PROGENITOR-0.
The Nexus Engine is a very resilient adversary and is capable of hitting quite hard; in addition, all of its attacks will drain the victim's power to fuel further assaults. It also has doubled energy, as all bosses do, and it is capable of summoning Voidstalkers to harass the heroes. It is immune to poison and wound conditions, and mostly resistant to stun, but its magic protection is only average, and it has neither arcane resistance nor damage protection. Its primary weaknesses are its mediocre Quickness and the high energy costs of its skills.
Cleaving Blow: A physical attack that hits the entire front line for moderate damage.
Dimensional Rift: Summons three Voidstalkers on any empty tiles.
Void Cannon: Targets one column for heavy damage. Any units defeated by this skill are disintegrated, preventing resurrection.
Conduit: (I'm not sure on the specifics but,) Progenitor-o, Nexus engine gains about 100 power points (when it is low on power) for seemingly no cost (dosen't take away from his action clock).
PROGENITOR-0 is extremely strong and durable, but its speed and lack of arcane resistance can be exploited fairly easily. Mages should use Freeze to slow it down while other characters deal with the lesser enemies around the Nexus Engine. Be aware that its turn WILL eventually come up ,and it will probably use a Cleaving Blow on the front line. However the main attack to look out for is the Void Cannon; while your frontline character may have enough health to weather this, the character behind them may not. If you have a warrior, make sure to set their fighting style to Guard to mitigate the damage to the back row. The Nexus Engine may also summon Voidstalkers on any empty tiles - use your Area of Effect spells to deal with them.
Once the machine is down to 100 power, have a Rogue use sap and any Mages use Power Siphon to keep it from using its powerful attacks. If one character manages to constantly suppress its power while the others continue to attack, PROGENITOR-0 should fall with minimum casualties.
Alternatively, most teams can take it down with conventional tactics due to its low speed, weak allies, and its reliance on high power attacks. Being the first true "boss" of the game, the Nexus Engine is more of a test of players' basic grasp of tactics and skill use than a genuinely difficult opponent; nonetheless, caution should be exercised.