The titantic monster unleashes its dragons breath. A blast of necrotic energy licks your heels as you duck out of sight, but the power of the attack flings the pieces of the statue to Orcus raining into the church. Oddly, the crude sacrificial knife rises into the air, and seems to draw some of the fell energy into itself, glowing a menacing purple as it hovers in the air.
Within the side tunnel, you do not find respite. A large, fiendish, dog-like creature is waiting for you, and breathes out its own fiery attack against you.
Make a DC 12 Dexterity save for half damage (always round down in 5e), and also roll Initiative.
Rolls
Fire breath - (6d6)
(623114) = 17
Initiative, hell hound - (1d20+1)
(3) + 1 = 4