Magic

Magic is a supernatural power that inexplicably exists in the world of (Un)Holy Crusades. It is present in three out of the five realms: the Realm of Order, the Realm of Dreams, and the Realm of Chaos. The inhabitants of these realms naturally know magic from the moment they are born/created, but mortals living in the Realm of Materials can also learn magic through imitating beings from other realms. The two mortal kingdoms have different ways of practicing magic based on almost completely opposite principles, due to their differences in culture and beliefs.

Astrean Magic: Prayers
Magic in Astrea is directly taught to its founders by the Sovereign, so most Astrean magical techniques, which are passed down as sacred prayers and religious texts, surround healing and facilitation of laws. Because magical prayers gain their power from the Sovereign, the stronger a caster's faith in Him is, the more powerful their magic becomes.

Devout clerics in the Astrean Church believe so deeply in the Sovereign that they have essentially given up all agency within their own lives, trusting their higher-ups (or in the case of the Archbishop, prophetic visions from the Sovereign) with everything even if it contradicts their own personal needs and desires.

Prayers have no effects when simply read out loud, but when combined with a holy relic and strong faith from their users, they can achieve supernatural effects. Only the Church knows how to create holy relics, and it is a closely kept secret.

Miasmian Magic: Spells
Magic in Miasmia was created by its inhabitants, including the Queen herself, researching and observing the behavior of the Six Gods every time they visited the Mortal Realm. Since the Six Gods are typically disguised and prefer to minimize interaction with mortals, many Miasmian magical spells derived from their behavior revolve around trickery and stealth.

Using magic requires memorizing complex motions and focusing one's mind on a spell's desired effects, so only those with strong intellect and imagination can become powerful spellcasters.

Commonly, spellcasters would grip onto staves or rods while they concentrate on using magic, as it not get lost within their thoughts and cause chaotic magical accidents.

Dark Magic: Curses
The magic of demons differ from the magic of gods, in that it is seemingly much more powerful, but also comes at a great cost. Since demons become stronger the more they embody "flaws" hated by the Sovereign, using demonic magic exacerbates these flaws within their users' minds. All demons are born knowing how to use magic, and the most prolific magic-users among demons are completely lost within their own minds, their personalities and the flaws therein amplified to cartoonish and over the top degrees.

The magic of demons, known as curses by mortals, can be casted using holy relics or the focusing staves of Miasmian spellcasters, for it is chaotic in nature, much like the realm from which demons originate.

Monstrous Magic
Some mortal beings who are based on mythical creatures possess magical abilities reminiscent of those found in their legendary counterparts known to humans on Earth. For example, dragons can breathe fire, basilisks can paralyze others by sight, and griffons strike fear into lesser beings with their presence. Seeing as there are no such myths describing these creatures in the Five Realms, these abilities seem to exist once again for completely arbitrary reasons.