Now that March of the Machine story has been fully released I can ask, how did your ocs weather the Phyrexia invasion of the multiverse?
Arnoss: Was on Ocaelum prepared to defend it from an invasion that never came. Now feels bad he did "nothing to help" during it.
Zarunpel: Worked alongside her sisters to keep her home and land safe even after the courts fell. The Alernis territory has the advantage of being closer to the Wilds and their influence, which the Phyrexians had a very hard time dealing with. It doesn't always make sense to Phyrexians which tend to be very scientific about things. Also, with the help of a couple of her sisters and borrowing her mother's sword, she fought @socialpoison's Traenor in his compleated arm and armor, and subsequently cut.
Ysara: She defended the Kaladesh village her home was nearby from. She died in the process, and left to her apprentice/assistant to clean up her skull and bring it to where she was from.
Farell: Heard about the troubles in Paliano, and couldn't resist coming to help Celin, the woman he loves. She was fine, though there was a lot destroyed. Also them being in contact again has led to exchanges about Farell's brother's death that makes everybody involved very sad, because they're living a tragedy.
Dolores: Thankfully her home on New Capenna was in the Mezzio, not on Park Heights. Her partner, @astrisjanus's Inza, stayed back on Capenna to fight the Phyrexians while Dolores herself took advantage of the chaos to go back to her home plane of Ferely. She was aiming to enact a vengeance there unnoticed. She was noticed.
Lhur: Recently consolidated his position on power and prepared his troops when he heard of what may be coming. When it happened, he saw no choice but to climb on his father's throne of shadows to coordinate actions and defense all across his country while channeling his own magic to limit the appearance of branches and portals over it. He emerged from the invasion exhausted, and then came the weeks more of exhausting work to manage the aftermath.
Jaspar: He was on Ikoria, in Indatha, trying to both survive and learn what he could of Nethroi and the Whispers. He fought how he could during the invasion and capped it off by using his magic through his Elderfang and spread over Indatha by Nethroi's whispers to call upon the echoes of Indath and essentially end Phyrexian (and some non Phyrexian) life in the area. He came back to Kaldheim to news of the death of his deity, Koma, and of the very foundation of Kaldheim. He doesn't yet fully accept the truth of that.
Alamir and Nksdv: They had been on New Phyrexia for intel and action for months by the time of the Invasion. Their last contribution to hinder the phyrexians was to remove their anti-planeswalker defense that scattered the assault team, before the Invasion even begun. It turned out to be a compleated planeswalker linked to Realmbreaker, @socialpoison's Ellidus. Alamir removed them and carried them away from the Tree, trying to reason with them and break through Norn's programming. Alamir knew what it was to be made and treated as a weapon and empathized with them. Seeing the planar instability before the end of the planar swap, Nksdv took them back to the Haven, and left Alamir to choose for themselves if they wanted to see the end of their world.
Sezashi: The orochi was fighting on Kamigawa, grown to oppose a compleated mech, and got stabbed by a branch of Realmbreaker in the back. He survived, and Norn's death rendered the oil inert before he could be compleated, though he might have a more metallic scar in his back now. While he was out, he received visions and ideas from the Myojin of Cryptic Dreams, but the Myojin is aptly-named, and he hasn't fully understood them yet.
Nyrhen: Fighting on another plane, then as soon as he got wind of the fact the attack was on every plane, went back to Eldraine to defend his Sanctuary in the Wilds. He killed a lot of Phyrexians that "happened" to find their way towards it.
The Cursetamer: She lost a lot of her collection of Apostates from Ferely on Innistrad and most of her planeswalking agents to compleation, and even she and her wife had trouble getting things under control after that. Her people actually helped her for once instead of the other way around, even if their home gave to Realmbreaker. Her latest Mana Core prototype was also lost, but that one self-destroyed before it could be compleated. Due to its nature, it had more safety features and contingencies than actual functions.
Kinahel: She was on Winrovah, fighting in a corner more desolate than average, in case she needed to use the Worldslayer or lose it into Void and hope for the best. Anything better than letting Phyrexians get their hands on it, even if she had no idea of the potential consequences. She burned herself out fighting and died as soon as she stopped (this is fine, she's a phoenix).
There's more but that's already plenty and I don't want to pollute people's timelines any more than that. If people want to know more about any of those or other characters, either for this arc or in general, you can ask!