Religion,as it's known to the inhabitants of Morgrad, is polytheistic. The gods play a significant role in the lives of men and mostly influence the world indirectly, utilizing servants, minions and avatars for their purposes. There are three gods featured in Gothic, Innos, the god of light, Adanos, the god of balance and Beliar, the god of darkness. All three of them are brothers, and constantly struggle in order to gain power over each other.
During the course of time there have been variations in their influence over the human civilization, alternating between Innos and Adanos. Worshipping those two is generally accepted and practised widely. Worshipping Beliar, on the other hand, is considered evil and unlawful, since sacrifice and death are considered the norm in dark rituals.
The gods play a central role in the series' plot, conspiring in the backround in the first two games and taking a more active role in the third one. The aforementioned struggle between the three gods has caused a lot of suffering and pain to humanity, until Xardas, with the help of the Nameless Hero, finally expelled them from Morgrad, forever.
Mentions concerning the fine tongue of Magic
The Gods
Innos
Innos is the god of the Sun, Light, Life and Fire[1]. The priests of his Cult are the Magicians of the Circle of Fire, or most commonly known as the Fire Mages. His holy warriors, the Paladin Order, are sworn to fight and banish the minions of Beliar, whatever the cost.
Innos is the original god, the eldest of the three brothers. He created his brothers by dividing himself, so that life would be possible[2] (See below, The Myth of Creation).
Beliar
Beliar was created by Innos, being his younger brother. He is the god of Darkness, Night[3], Pain, Suffering and Death.[4]. He is the least popular god, yet his followers, in exchange for their sanity, are granted great dark powers. Beliar commands a variety of undead creatures, dark beings, dragons and black mages, such as necromancers and a group of powerful,hooded individuals called The Seekers.
Adanos
Adanos is the god of Balance, water being his domain, an element that allows chaos and harmony to coexist in peace. His priests are the Magicians of the Circle of Water and they are assisted by the Ring of Water, who act as paladins for the Water Mages in secret.
Another group that worships Adanos are the Druids of Myrtana, who are in turn assisted by the Rangers. They take extreme measures to maintain peace and order, often going as far as killing enslaved humans.