War Historian

Green needed a body willing to shove itself into a siege, and the design solution here is a conditional that only pays out when the creature actually goes on the offensive: it becomes indestructible the turn it attacks a battle, and only that turn. That single clause is the whole trade. Sieges sit behind an opponent's blockers, so pressing an attack into one means committing a body through a wall of defenders to knock the defense to zero and claim the transformed reward. A creature that survives destruction-based removal and lethal combat damage on the turn it makes that charge is precisely the incentive that kind of assault was short on: it can eat a block, shrug off a targeted answer, and still bring the defense down. Reach keeps it earning its keep on the turns it stays home, holding the ground against fliers while you are not laying siege. The key discipline is that indestructibility is a reward keyed to one line of play rather than a standing keyword, which is why green can hand it out at this rate: it costs nothing until the creature swings at a siege. Off the attack it is a 3/3 with Reach and nothing else, and that is the honest read. This is clean support for a mechanic that only functions when there is a siege to break, a body purpose-built for exactly that job and unremarkable outside it.