Mythical Units and their Use

In all its worlds, Grepolis gives you the possibility to recruit mythical units. They are directly linked to a god, i.e. the god of the city they are recruited. All gods allow the recruiting of Divine Envoys. Each god has two mythical units that are unique to them. The god worshiped in a city determines the mythical unit types you can recruit in it's barracks. To recruit mythicals, you need resources of wood, stone, and silver; as an added ingredient you need divine favor.

Before we go into details relevant to each unit available in Grepolis, there are a few things you must be aware of. Neglecting this basic information could be a costly mistake.

A city needs and has a god. That god determines the mythical units you can recruit in the barracks. The ability to recruit mythical units depends on how many levels the temple has been built up to. The barrack's level of building is not relevant; as long as you have barracks, you can recruit mythical units. Mythicals don't need to be researched. This is different to regular land units; their recruitment is dependent on the level of barracks build up and on research.

If you change the god you worship in a city, any mythical unit you recruited in that city will instantly die. While Divine Envoys look the same for each god, they will disappear with the rest if you change the god you previously worshipped.

Mythical units can't be stationed in other cities worshiping another god than the one they were recruited with. A Pegasus recruited under Athena can only defend another city with Athena as the god or obviously its home city. A ghost city has no god; for the mythical units, that is like another god. If you conquer a ghost city with mythical units in the mix, the conquered ghost city automatically takes on the god of the mythicals.

Mythical units use divine favor as an additional resource to wood, stone and silver. The Divine Envoy uses only divine favor as a resource. Most mythical units are not as good as they appear to be. The wiki figures for attack and defense points are per unit; breaking them down points per population used or comparing the amount of resources that are needed is sobering.

The mythical units are:

The Divine Envoy
Calydonian Boar 

Centaur

Cerberus

Cyclops

Erinys
Griffin

Harpy

Hydra

Manticore

Medusa

Minotaur

Pegasus

The Divine Envoy

God: all gods (but they must have one)

Barracks minimum: Level 1

Temple minimum: Level 1

Plus: No regular resources like wood, stone, or silver needed; fast recruitment; when included in a Colony Ship attack, the conquered city will worship the same god as the attacking city immediately.

Minus: Not best at attack; not best at defense; uses 3 population; when included in a Colony Ship attack, the conquered city will worship the same god as the attacking city immediately.

Useful: To open up farming villages in a new city without using regular resources.

Calydonian Boar
God: Artemis
Barracks minimum: Level 1
Temple minimum: Level 10

Plus: High defensive values; cheap in resources and favor.

Minus: Low attack value.

Useful: Good defensive unit.

Centaur

God: Athena

Barracks minimum: Level 1

Temple minimum: Level 14

Plus: Cheap in resources and favor.

Minus: Not best in attack; average in defense.

Useful: Can be used to steal divine favor to build Pegasus.

Cerberus

God: Hades

Barracks minimum: Level 1

Temple minimum: Level 10

Plus: High defensive values; cheap in resources and favor.

Minus: Low attack value.

Useful: Good defensive unit.

Cyclops

God: Poseidon

Barracks minimum: Level 1

Temple minimum: Level 12

Plus: Good attack value; decent defense values.

Minus: Slow.

Useful: Can be used to steal divine favor to recruit Hydra.

Erinys

God: Hades

Barracks minimum: Level 1

Temple minimum: Level 16

Plus: High attack value.

Minus: Needs transport off island; expensive in resources and favor; average defense values.

Useful: No.

Griffin
God: Artemis
Barracks minimum: Level 1
Temple minimum: Level 15
Plus: Flying unit, ignores ships in harbor; doesn't need transport ships or escort of attack ships; high loot value. High attack value. Can build 2 at a time due to resource requirement (as opposed to Manticore).

Minus: Expensive in resources and favor; bad defense. Not as fast as Harpies.
Useful: The ultimate attack unit with blunt weapons; perfect nuke.

Harpy

God: Hera

Barracks minimum: Level 1

Temple minimum: Level 5

Plus: Flying unit, ignores ships in harbor; doesn't need transport or escort of attack ships; high loot value; fast; cheap in resources and favor.

Minus: Low defensive values. 

Useful: Harbor spies; looting on and off island.

Hydra

God: Poseidon

Barracks minimum: Level 1

Temple minimum: Level 22

Plus: Higher attack value than light ships, higher defense value than biremes per population used. Hydra can't be sunk by fire ships.

Minus: Expensive; as slow as slow transport.

Useful: If you plan a slow transport nuke, Hydra is the perfect fit. Can't be touched by Fire Ships which reduces losses when taking a city.

Manticore

God: Zeus

Barracks minimum: Level 1

Temple minimum: Level 15

Plus: Flying unit, ignores ships in harbor; doesn't need transport or escort of attack ships; high attack value; fast. 

Minus: You can only build one at a time; expensive in resources and favor; bad defense. 

Useful: The ultimate attack unit with sharp weapons; perfect nuke.

Medusa

God: Hera

Barracks minimum: Level 1

Temple minimum: Level 10

Plus: Good attack value. Good defense values.

Minus: Needs transport off island.

Useful: In both defense and attack.

Minotaur

God: Zeus

Barracks minimum: Level 1

Temple minimum: Level 10

Plus: Good value in overall defense; decent attack value.

Minus: Needs transport off island.

Useful: In defense; farming on island.

Pegasus

God: Athena

Barracks minimum: Level 1

Temple minimum: Level 12

Plus: Flying unit; high defensive values; fastest unit in the game; cheap in resources and favor.

Minus: Low attack value. 

Useful: Harbor spies; defense of cities at a distance especially when on neighboring islands.