Grail building

The Grail building, called Grail Sanctuary in Olden Era, is a type of building in Heroes of Might and Magic series first introduced in Heroes of Might and Magic III that has appeared in every game since. It replaces the Ultimate artifact that appeared in Heroes I and Heroes II.

The Grail building is the supreme building in the town, which provides many bonuses. Usually, the Grail building offers a great gold income and a huge bonus to growth rate in the town, and also provides an additional bonus effect based on the type of town it was built in. Constructing a Grail building requires a hero to carry a special, powerful artifact to the town, either the Grail in Heroes III, IV, and Olden Era, or the Tear of Asha in Heroes V, VI, and VII. Typically, only one Grail building can be built in a game and only near the end of the game.

Heroes III

The Grail building in Heroes III provides the kingdom with 5000 gold per day, increases creature production by 50% and gives an extra effect.

Faction	Name	Image	Additional effects
Castle	Colossus		Increases allied heroes' morale by 2.
Rampart	Spirit Guardian		Increases allied heroes' luck by 2.
Tower	Skyship		Reveals the entire map, and provides 150 spell points to defending hero during a siege (not retained after combat).
Inferno	Deity of Fire		Every week becomes the Week of Imp, which increases the creature growth of imps and familiars.
Necropolis	Soul Prison		Increases allied heroes' Necromancy skill by 20%.
Dungeon	Guardian of Earth		Increases the defending hero's Spell Power by 12 during a siege.
Stronghold	Warlords' Monument		Increases the defending hero's Attack by 20 during a siege.
Fortress	Carnivorous Plant		Increases the defending hero's Attack and Defense by 10 during a siege.
Conflux	Aurora Borealis		The town's mage guild contains every spell.

Heroes IV

The Grail building in Heroes IV increases gold income by 3000, and provides a bonus to magic spells.

The exception to this is the Stronghold faction, which increases the creature growth. While the text mentions increasing the creature boost of towns of Stronghold faction, it actually increases any allied town's creature growth.

Faction	Name	Image	Magic School	Spell increase	Additional effects
Haven	Holy Avatar		Life	50%	N/A
Stronghold	Festival of Life		N/A	N/A	Doubles the creature growth in the town, and all other allied towns gain 25% to creature growth.
Academy	Great Library		Order	50%	Any Academy town's mage guild contains spells up to level 5, regardless of the level built. If the hero stays in an Academy town with a mage guild, they gain 25% mana points extra for each level of the mage guild constructed beyond level 2.
Preserve	Summoning Stone		Nature	25%	N/A
Necropolis	Infernal Effigy		Death	50%	Increases the effects of Necromancy skill by 50%, and increases the cap of raised creatures by 10%.
Asylum	Eye of Chaos		Chaos	50%	N/A

Heroes V

Similar to Heroes III, the Grail building in Heroes V provides the kingdom with 5000 gold per day, increases creature production by 50%, and gives an extra effect.

Faction	Name	Image	Additional effects
Haven	Elrath's Sentinel		Increases allied heroes' luck by 2.
Inferno	Lord of Torments		Increases the defending hero's Spell Power by 10 during a siege.
Necropolis	Tomb of the Lost		Increases allied heroes' Necromancy skill by 50% and provides them with 150 points of Dark Energy.
Sylvan	Daughter of Sylanna		Increases allied heroes' luck by 2.
Dungeon	Mother of Darkness		Increases the defending hero's Spell Power by 10 during a siege.
Academy	Skyship		Increases the defending hero's Knowledge by 10 during a siege.
Fortress	Blazing Anvil		Increases the defending hero's Spell Power by 6 and defending creatures' Defense by 6 during a siege. Defending Runemages can use Runic Magic without spending resources.
Stronghold	Tower of the Khan		Increases allied heroes' Attack by 4.

Heroes VI

The Grail building retains the same function in Heroes VI as it did in the previous installment. However, it can only be built in a town with a capitol building, and has an additional cost of 15 wood, 15 ore, 15 crystals and 15000 gold. It gives out 5000 gold per day and a bonus of 50% creature growth in the town.

Faction	Name	Image	Additional effects
Haven	Elrath's Infinite Mercy		After each combat, a third of slain creatures are revived.
Necropolis	Asha's Undying Resolve		Increases the effects of the Necromancy skill by 100%.
Inferno	Urgash's Fiery Wrath		Inflicts 1000 Fire damage to the enemy hero's creatures within the town's Area of Control, and inflicts that much damage to enemy creatures besieging the town each turn.
Stronghold	Father Sky's Furor		All Stronghold creatures begin with Rank 2 Bloodrage at the start of combat.
Sanctuary	Shalassa's Frozen Breath		There is a 50% chance that if a creature receives a "Chilled" status (halves the creature's movement) from the hero or its creatures, it is replaced by "Frozen" status (makes the movement 0).
Dungeon	Mark of Malassa		The duration of poison, mind control, and invisibility effects are increased by 1 turn.

Heroes VII

The grail retains the same function in Heroes VII as it did in the previous installment. It costs 5 wood, 5 ore, 5 dragoncrystals, 5 starsilver, 5 dragonsteel, 5 shadowsteel and 4000 gold, and needs the town level to be at level 15.

Faction	Name	Image	Additional effects
Haven	Elrath's Infinite Mercy		After each combat, 10% of fallen creatures are revived.
Stronghold	Father Sky's Furor		Stronghold heroes start with 4 additional Bloodrage.
Academy	Arcane Portal		+100 maximum mana to all allied heroes.
Necropolis	Asha's Undying Resolve		Increases the effects of the Necromancy skill by 10%.
Sylvan	Sylanna's Perfect Balance		At the start of the combat, each Sylvan hero marks every enemy creature.
Dungeon	Mark of Malassa		Spies can plunder and sabotage two additional map objects.
Fortress	Arkath's Eternal Flame		Provides four major and four relic artifacts and The Fire Drake artifact when built.

Olden Era

In Heroes of Might and Magic: Olden Era, the Grail Sanctuary does not cost any resources, and boosts the growth rate of creatures in the city by 100% in addition to a bonus effect.

Faction	Name	Image	Additional effects	Flavor Text
Temple	Golden Calf		The owner's cities produce 1000 gold and 1 of each other resource daily.	The Splendor of the Sun must reach all that wish to see it. May the Era of the Chalice begin!
Necropolis	Everserpent		All friendly creatures gain +10 Defence and take -50% Lucky Strike damage in battle (including from spells).	The necromancers have coveted the secret of dragon reanimation for centuries. Now, that secret is theirs to keep.
Sylvan	Spring of Life		Provides additional growth in all cities.	All life is sacred. All life is everflowing.
Dungeon	Spy Network		Completely removes the fog of war for the owner.	For every general and noble in Jadame, there are three sets of eyes watching their moves in the name of the Triumvirate.
Hive	Chorus Conductor		All friendly creatures gain +10 Attack in battle. All friendly heroes, hero spells, and creatures gain +50% Lucky Strike damage.	They heard their Master direct them and they sang in unison and bliss.
Schism	Firmament's Abyss		Building a mage guild in this city unlocks all spells of the corresponding tier.	What is the sky's firmament if not a reflection of the Abyss?