EARLY GAME: The first few turns you want to spend ramping into Unesh, playing other small CMC cards whenever possible. Try to save your changleings for when Unesh is on the field. Hold up counterspells to prevent early combo wins, Mystic Remora & Rhystic Study to draw extra cards early, Gilded Drake to shut off other commanders or big scary creatures. Absolute best case scenario, you can cast Unesh on your first turn, with one way to get trigger Unesh's BFOF (baby fact or fiction). If you do this, you will be FAR ahead of your opponents. Turn 2 is a possibility which will also put you well ahead. Turn 3 is still great, and you will play him turn 4 on average. You can enter mid game when Unesh is on the field.
MID GAME: PROTECT UNESH. Use the interaction you pick up from Unesh's ETB. Continue to ramp as much as possible to be able to replay him if you need to. Play some lightning rods (lightning rods: other important spells that draw out removal). Lightning rods such as Tezzeret the Seeker require interaction, making your opponents less likely to target Unesh. Bounce Unesh with cards like Snap or Unsummon to protect yourself from paying commander tax. Smart opponents will continue to remove Unesh because they will know your strategy revolves around Sphinxes trigerring his BFOFs. You want to be looking at as many cards of your deck as you can, while keeping your opponents' threats at bay with counter magic and removal. While Unesh is on the field he will generate incredible value for you by saving mana and putting cards in your hand! Eventually you will have enough value, combo pieces, or battle damage to win the game.
LATE GAME: You don't typically see late game in cEDH. In cEDH it is a battle to prevent opponents from winning every turn. And if an opponent wins, this precludes your victory. Knowing what spells to counter and interact with is paramount. Knowing if your other opponents can help you prevent wins is also important. Talking about late game in cEDH doesn't make much sense when everyone is trying to combo off every turn.
WIN CONDITIONS:
- Battle damage: Sphinxes are big boys and they hit. On average it only takes 10 sphinx attacks to take someone out of the game.
- Deck yourself and cast Thassa's Oracle: Play enough low cost sphinxes to get through your deck and cast Thassa's Oracle. See 20% rule below, but essentially having your deck comprised of 20% sphinxes will allow you to deterministically find more sphinxes to keep rolling through the deck. You don't need bombs like Rite of Replication to do it. Also Rite will almost always be countered, too risky to play in cEDH.
- Shoot your opponents with Aetherflux Reservoir: You will be able to cast a lot of spells each turn making this win con feasible. With Cloudstone Curio & Universal Automaton on the field, while you cast non-artifact sphinxs, you can double your Unesh triggers and storm count. (Although Universal Automaton doesn't trigger Cloudstone, it can be targeted by it.) If you need the last couple of casts in a turn to win the game, using Chain of Vapor on all your cheap sphinxes can get you there. Also, this is notably the only life gain in the deck. Hopefully you won't need to gain life because Unesh wants to win before this becomes a problem. Aetherflux does have an infinite combo in this revision with Shrieking Drake, Cloudstone Curio, and Defiler of Dreams. The combo is described below, and it can eb done with other cheap changelings while Unesh is on the field.