Core Augur. Concise, elegant, and far less… showy. I don’t need to try to intimidate people with my name. I can let everything else do that for me.

During the war, our councils were almost weekly, unified as we were against our common foe. Now? Infrequently and irregularly, and rarely do all five of us attend. It’s something of a bittersweet development. I miss the time when we could stand united, but at the same time I’ve never had a great fondness for my siblings.

Excellent. Thank you again, my friend.

Kill: Bolas
What? If the option ever truly presented itself, I would be a fool to turn it down. No offense meant, Lord Bolas, and I have no illusions as to whether I actually could slay you. Still, I have no doubt that you would do the same in my situation.

Marry: Ajani Goldmane
A charismatic, noble warrior whose magic exalts and magnifies the greatest virtues of those around him. Truly a valuable ally. Besides, I’m tired of Norn getting all the leonin.

Fuck: Garruk Wildspeaker
Note that, since I lack genitalia, this is meant in the sense of “screwing one over,” to use the vernacular. Granted, the beastmage has already endured much, but since I neither fear nor respect him to any great degree, he falls under here by default.
I suppose I could splice his genome into one of my larvae, but I see no reason to do so. I have no need of hirsute, meatheaded children who smell of a tanadon’s backside. 

Dr. Yagokoro! I admit, I hesitated to announce my return to you; I was unsure if you remembered me, or if you wanted to. That you reached out to me warms my hearts. Thank you.

Well if you didn’t want them dead, why did you ask? I’m sensing some conflict here.

As for my sororicidal plans, I’m certainly not going to outline them where Norn herself can see them.

Also, I take this opportunity to assure my esteemed sibling that the only plans I have to kill her and assimilate the Machine Orthodoxy into the Progress Engine hinge on her making the first move. Don’t stab my back, dear sister, and I won’t stab yours.

In order:

Jarad: Reanimating yourself after dying is impressive. Squatting in rot beneath an unsuspecting populous while plotting your conquest? Now you’re just stealing our schtick.

Niv-Mizzet: Much like Nicol Bolas, to be respected as a genius who could crush me between his talons in a fair fight. Unlike Bolas, probably far more amenable to a collaboration between our respective organizations.

Trostani: Laughable. We’ll see what chord glistening oil strikes in the Worldsoul.

Rakdos: Makes Vorinclex look like a model of restraint and responsibility. Needs to be put down like the rabid dog he is.

Isperia: Like most sphinxes, insightful, yet short-sighted. Her laws are artificial restraints, not those hard-coded into reality itself, yet she thinks them to hold equal authority. She will see how mistaken she is when society collapses around her.

The Obzedat: Another example of those whose power is intrinsically tied to a societal fabric. Wealth is not power, merely a facilitation mechanism to ease transactions. Ghosts have no place in Phyrexia, and gold serves only as material for white mana capacitors.
Teysa Karlov, meanwhile, seems far too clever to be trusted. If she cannot be brought to our side, she must be eliminated posthaste. 

Aurelia: As always, I leave angels to my esteemed sister. I look forward to seeing what she makes of this one.

Borborygmos: At least Rakdos has a motive. This brute seems to smash for the sake of smashing. Vorinclex is welcome to him.

Lazav: Admirable. Sheoldred in shapeshifting form. If its own machinations don’t horribly backfire, I may have to kill simply so the two of them can never collaborate.

Zegana: Could it be? She seems dedicated to forging a compromise, nay, a partnership between my philosophy and Vorinclex’s. Incredible, simply incredible. I am fondly reminded of Kiora Atua. I do hope she will see Phyrexia as the ultimate adaptation to a hostile Multiverse. If not, I may have to employ more aggressive recruitment tactics.

Because he’s my brother. Can’t you say the same of your siblings?

For the first question, my first impulse is to say Vorinclex, but Glissa would take his place almost immediately and be vastly more competent and dangerous. As such, I’m going to have to say Elesh Norn. Her subordinates would have no idea what to do without her guidance, and I could easily swoop in and consolidate them.

As for who I would become… Ugh. Sheoldred, I suppose. Least intolerable of all choices, and at least she and I have vaguely similar moda operandi.

I admit, I suspected they were using anonymity to protect themselves from your wrath. At the time, I thought it best to let them stew in their fear.

In the event that you locate any of them, be sure to save me the brains. We both know you just throw them away or eat them, and I have psychosis crawlers in need of further nervous tissue.