Bastion Inventor

Improvise turns artifacts into temporary mana, a bargain on a spell whose ceiling is a body, and the body here is the entire point: a 4/4 that opponents cannot touch with removal or targeted disruption. The trade is that improvise rewards a board already cluttered with cheap artifacts, the same shell that wants those artifacts for other reasons, so the discount is realest in exactly the deck that least needs help curving out. What it buys is durability rather than tempo. Hexproof on a midrange artificer body is a different proposition than hexproof on a hexproof-aggro one-drop: this is not a creature you suit up and race with, it is a creature that simply stays on the table while spot removal slides off it, demanding a board wipe or a chump block to answer. That makes it less a finisher than a clock that opposing interaction cannot interrupt, which is a quieter kind of pressure than a 4/4 normally implies. The improvise text and the hexproof point in the same direction (lean on a wide artifact board, then land a threat that survives the cheap answers) without ever quite combining into something explosive; it is a sturdy, honest piece for a build that already has reasons to keep a stable of artifacts on the table.