So, this is where the bats came from. The church and ringing bell give him pause. Gods and ghosts are both uncanny, and trouble him. Not enough to stop him, though. 

The fence isn't enough to stop him either; he cuts his way through and strolls up the hill. 

The door of the church is ajar — the better to swoop through ­— and the interior is gloomy. It is somewhat hard to see, but he can still make out the pews, and the shifting mass of bats that cover the ceiling.

"Eeek-ik," one of the bats calls to him, by which she means "The Boy says we mustn't let you in. If you come inside, we'll have to stop you."

Any fear and trembling suppressed, he swaggers into the church, sword drawn. 

“Stop me, then.”

The bats watch carefully as he approaches. And then, when he walks through the door and into the right spot ... now!

[Bombs away] (5 Treasure) — Once per challenge, non-portable, triggered
    When the invaders step under the right section of the church’s ceiling, the bats drop their bombs, dealing one damage and setting the invaders alight.

The bats push a small incendiary off of a little platform near the ceiling, lighting it with their magic as it falls. It lands on his head, setting his hair alight.

Whoa! Fire! Onfire!

1/2 health

He backs right out of the church, drops to the ground, and rolls down the hill to put himself out. 

The bats weren't really expecting that to work, honestly. He seemed pretty scary when he bisected them.

They chatter among themselves, but the consensus seems to be that if he's going to leave after getting set on fire, then that is fine.

They cluster around the opening of the door, watching to see what he'll do next.

Once no longer in fire, he notices the bats clustered together at the door. If they aren’t going to press the attack— he will. Back up the hill he goes, sword in hand. 

Ah! They didn't think he was coming back!

The bats scatter back to their stations, momentarily filling the air with a wheeling cloud of black wings.

He gives them a disappointed look, as his sword slices through the cloud of wings.

Cut: every turn, at will, portable (10 Experience)
The basest principle of sword law. Cut the enemy. 5 damage.

The Bats are no more resistant to his sword than they were the last time. The way into the church is no longer barred.

He is a bit disappointed that the bats are no more resistant. Though, their use of the firebombs is reassuring. They are not totally lacking in killing intent. 

Into the church, taking a look around. 

The church is empty — and gloomy, making it hard to see. The pews provide a perfect ambush spot, although nothing seems to be taking advantage of it. Behind the altar is a large, solid door. Unlike everything else in the church, it seems well-cared for — and has a prominent iron lock.

Dust floats through the scant beams of sunlight, swirling in unpredictable patterns. Tracks through the dust lead from the door up to a staircase along one wall, that spirals up into the spire.

That lock looks sturdy… but is it 5-damage-sword-attack sturdy? Best not to find out. It would be unpleasant going into battle singed and with a dull sword. So up the stairs he goes.

The room above is dusty, drafty, dim, and dull. In it, a small boy stands hunched by the far wall, curled around something and whispering. The center of the room is dominated by a large brass bell.

“Boy! I am searching for a key. Do you know and will you tell where I can find one?”

He jerks up and spins to confront Red, revealing that he's holding a bat (the wooden kind) in his hand as he does.

"A key?" he replies. "A key? You've come to take my key from me! Just like you took— No! I won't let you!"

He lashes out and beats the bell with his bat, blasting the intruder with sound and dealing two damage. The sound also stuns Red for one turn, allowing the boy to stalk toward him, thwacking the bat menacingly.

He has in fact come to take the key, and so the sonic violence to defend it is rightly done and correctly aimed. 

-1/2 health

He’s the sort of dungeon monster that gets as close as possible to dying before disintegrating and being recreated by his core. (At his request, it would be wrong for him to just vanish or turn to dust quickly upon death.) Normally this would also involve coughing out some last words, but he is too stunned by the ringing for any of that.