
The battle against Amon would've gone easier if they'd just "Kicked the can down the road".
I know this is supposed to be a reference to. Artanis is unconcious, Kerrigan is still blubbering, and Raynor has a cybernetic arm. In a flash of black energy, it shifts to the Spear of Adun.
He starts getting torn apart from the inside by tentacles, speaking aloud "ALL SHALL SPEAK IN ONE VOICE!" Raynor is clearly terrified, trying to snap out Kerrigan and Artanis. Amon seems outright confused, before starting to scream like Artanis.
Artanis starts screaming insanely, hearing "All shall speak in one voice or forever be silent" repeating in his mind. She hears the words "Speak in one voice" in her mind. He shakes it off but suddenly, Kerrigan falls to her knees. but then, Raynor notices his visor is flashing faint words. How Lot V will endEveryone is facing down Amon, preparing for a final battle. Although it's only a single character and it works on a timer rather than a revive mechanic, you can only have one and it's a unique unit.
The Deploy Fenix ability is quite similar to this. Artanis could fall on the field of battle and come back as a colossus. Maybe even a robotic simulacrum of their old bodies to give an excuse for continual training of a unit that looks like Zeratul classic. What if the Protoss used the tech from the Spear of Adun to improve their resurrection tech and now have unique machines to place their heroes in? The immortals can be used for most warriors but special heroes like Zeratul or Artanis (if they die at any point) get their own special machines. In canon the Protoss already have a method of raising the dead (think Immortals or Dragoons) and Fenix has already been brought back from the dead. They already have the Mothership which is immensely powerful, can be reconstructed and which you can only train one of.
The Protoss will be able to train heroes and revive them after deathIt would definitely fit in with the Protoss style of quality of quantity.