Six brothers, six special effects, and the exact chest rates by kill count — from 1 in 11 up to guaranteed.
Barrows is a repeatable loot run. Six brothers lie in six crypts in Morytania. Kill all six, then loot the chest in the tunnels below for a chance at Barrows armour and weapons.
Getting there
Detail
Value
Location
The Barrows mounds, Morytania
Teleport
Teleport menu > Minigames > Barrows (10,000 coins)
Requirements
None. Bring a spade to dig into the mounds
Bring
At least 5 free inventory slots for the chest (extra loot goes to your bank)
Mechanics
Brother
Combat
HP / max hit
Style
Ahrim the Blighted
98
90 / 19
Magic
Dharok the Wretched
115
120 / 25
Melee
Guthan the Infested
115
120 / 23
Melee
Karil the Tainted
98
90 / 17
Ranged
Torag the Corrupted
115
120 / 20
Melee
Verac the Defiled
115
120 / 25
Melee
Pray against each brother's style. Verac can hit through Protect from Melee, but those hits are capped at 13. One brother, picked at random each run, waits in the tunnels instead of his crypt.
The chest room opens once 5 brothers are dead, but the chest only pays when all six are dead. Kill every brother before you open it.
Rewards
With all six dead the chest makes seven rolls, each about 1 in 102 for a Barrows piece, so about 1 in 15 per chest. You never get the same piece twice from one chest. It also always gives runes (death, chaos or blood), bolt racks and a potion.
Degraded Barrows gear is repaired for 80,000 coins a piece.
Drop table
Taken straight from Ashmarch's own drop data. Rates are per kill on Regular mode with no drop-rate bonus.