This deck wants to be able to play mid-late game wins. As midrange deck at its core, ideally we are using artifacts to pump up our Battlemage and keep up pressure, sneaky creatures to ensure removal gets wasted early (and isnt saved up for our Vampires or Megamoebas) as we continually shrink/pollimorph any big threats so our mage can smash them. We pack in late game inevitability of Land Deed + Megamoeba combo (bonus points if you draw into Seven league boots which should be basically instantly backbreaking for our opponent) and lots of mobility to control the board and grapple shots to close out the game once we pull ahead.

• Notable interactions:
• Battlemage loves weapons. We throw in a single Battlefield in case we can get one back late game.
• Daperyll Vampire lets us regain health our battlemage loses from swinging on minions. He really wants to land hits with Flaming Sword, and is a primary target to hold our Screaming Skull or Torshammar Trinkets to maximize that life gain and damage (note that splash from swords doesn't also heal, though, because that damage come from the sword.)
• Blink, Flanking Maneuver, and Teleport will let us get our battlemage where he is needed, whether that's Shrinking and Pollimorphing a big creature (those spells have limited range) or just getting around to land hits on sites. We also don't mind spending these cards to let our Mage play wack-a-mole on little guys, as that draws us more cards while keeping the board clear. As a mid range deck, we can't let our opponent amass a bunch of dorks, we want to get rid of them and get more cards in hand.
• Undertow lets us grow our 'Moeba for free, or get our Avatar into/out of position. Mobility is king.
• Ruler of Thul (and to a lesser degree, Polar Explorers) facilitates the plans above by pumping our mage or our bears or vampires that have made it to the opponent's back line, or letting the Moeba get across the board to grow further. He is a terrific creature in a deck playing so many weapons, as he can grab and use a Flaming Sword or Screaming Skull right away.
• A recent addition is the 2x copies of Phantom Steed which help us with the theme of being difficult to control and growing the 'moeba, but very importantly also allows us to setup inconvenient attacks for our opponent, and maximize use of an otherwise costly "do nothing" card that we are packing, the Land Deed.
• Notable Omissions:
• Floodplain felt unnecessary the first times I played this deck. It ended up back in the list to ensure threashold for polar explorers and moebas, and extend the range of our undertows.
• Undertows: a cute moeba-growing or mage-moving action, but overall too good for the theme of the deck. Must have 3x.
• Replication could be great in this deck, would need to test it.
• Spectral Stalker feels awkward since we have no voidwalk synergies, and getting over to their side of the board to hit a site is just as fast, and safer if we play a bear on our side, then swing "backward"; That 2 mana 1 air threshold is very tempting though, and may prove worth slotting stalkers in with more testing (trading out a number of mobility or shrinking spells)
• Selfsame Simulacrum could be great as a second Ruler, Vampire, or 'Moeba. Not sure if it is worth playing in this deck though. A great play would be copying their best creature before sleeping/pollimorphing it.
• Questionable Choices:
• Dodge roll got cut.
• Up to 17 minions now, and many are fragile, dying to 3-damage fire and air removal, not even necessitating bury or drown (both of which work perfectly as we have no submerge or burrow minions)
• I'm only testing against friends, so no sideboard exists presently. I'm not sure what the correct inclusions in a typical water/air sideboard are, but obviously dealing with fire + lightning spells (?) drown/bury effects (all terrain vestments) and artifact/aura removal (disenchant etc) would be at the top of the list.