Hero Siege Book of Belial - Relic Effect and Tier Values

Book of Belial is a relic, not a weapon or an equippable book — which is the first thing to get straight, since the name suggests otherwise.

What does the Book of Belial do?

It grants Satanic Chant, a usable ability described as: when cast, temporarily boost your Damage.

Relics in Hero Siege scale across tiers, and this one’s attack damage bonus scales steeply:

Tier	Attack Damage
1	5%
2	25%
3	50%

The gap between tiers is large enough that a tier-1 copy and a tier-3 copy are effectively different items. A 5% temporary boost is marginal; 50% is a real cooldown to plan fights around.

Why do sources disagree about the effect?

They do, and the disagreement is worth knowing rather than resolving silently.

The current wiki lists the tiered attack damage values above. An older Fandom entry describes the relic differently:

On use doubles all damage done by player

“Doubles all damage” and “+50% attack damage at max tier” are not the same effect. The most likely explanation is that the relic was rebalanced and the older entry was never updated — which is the same pattern seen across this game’s community wikis, where pages freeze at whichever patch they were last edited in.

Trust the tiered values as the more recent and more specific description, and confirm in-game before building around the effect.

Is the Book of Belial worth using?

As a usable relic, it competes for an activation rather than a passive slot, so it is worth it when you have a moment to use it — boss fights and dense packs rather than general clearing.

At tier 3, a temporary 50% attack damage boost is meaningful for physical builds specifically, since attack damage is what their output multiplies from.

What are relics generally?

Hero Siege has over 170 relics, which are passive, usable or orbiting. Book of Belial is the usable kind. Others in the same catalogue are purely passive — Bonsai Tree grants vitality and magic find, Charmed Blood grants life steal — and each scales across the same three-tier structure. See the full relics catalogue for the rest, or items generally for how rarity and tiers work across other equipment slots.

Next step

Check which tier of the relic you actually hold before planning around it — the 5% and 50% versions carry the same name and behave completely differently.