“You don’t sense it?” The Ur-Didact continues to stare at the ring of pillars. “This is how we will know they’re coming.” He turns and glares angrily. “What wisdom have you acquired, buried in my pattern, in the shape of my flesh? Am I to be set aside, and you, no doubt screaming under all that pattern, perhaps hope to return to what you were? Or do you find this pattern more suitable—and hope to replace me?”

“The Lifeshaper and I have work to finish. And so do you. There are no plans to set you aside.”

“You still can’t read her as well as I. She is stubborn, brilliant as a nova, dark as a singularity, with infinite depths. I’ve never discovered the core of her emotions, her self. I wonder what her duplicate would be like, what it would feel like to wear her imprint. To so many species she has made herself like unto a god, that they will remember her, that she can manipulate them in future times. She’s explained that to you, hasn’t she?”

“I remember.”

“Second-hand memory!” The Ur-Didact rises and stretches out his armor. The hard light sparks with emotion. “You’re a poor copy at best, aren’t you?”

Catalog is concerned that the long conflict may now turn physical.

The Ur-Didact approaches his duplicate.

They stand barely separated by the reach of their great arms, surrounded by the swirling mist, the sough of the light breeze, the rhythmic lap of wavelets.

“There is no hope, continuing with your strategy, not in our time, not in this galaxy,” the Ur-Didact says. “That is a cold, simple fact.”

“I hold another opinion.”

“Your privilege … Manipular.” The Ur-Didact’s expression is disdainful. “The Halos? Violating the Mantle all over again, with even greater destruction! Wiping out all intelligent life across this galaxy! By itself that proves you are a poor version. You’ve altered your strategic vision.”

“According to circumstance, as every commander must.”

“Don’t you feel the truth of it? We gave the Precursors reason to retreat into madness. A passion for vengeance. And the Gravemind gave it all right back to me. I am filled with that passion, that madness, that poison! If we fire Halo, we lose everything.”

The two Didacts stand opposite each other, barely moving, barely breathing, as if sizing each other up. Their armor is evenly matched. Their weapons are identical, their defenses, identical.

But the Didacts themselves—no longer identical.

“I leave the Lifeshaper to you, Bornstellar,” the Ur-Didact says. “She has obviously chosen your way, not mine. I will take my own ship and you will show me where the Ark has been hidden.”