It seems vaguely to be:

• Blood-based magic (from all the enemies with an Oriq Mask from the Strixhaven sourcebook)
• Magic of mass destruction / slaughter (from the STA Day of Judgment flavor text)
• Magic made for "endless war", whatever that means (from the STA Village Rites flavor text)

It may be left ambiguous in the sourcebook so that you have the opportunity to make up evil spells, banned relics, or forbidden techniques in your game that your players encounter.

It seems vaguely to be:

• Blood-based magic (from all the enemies with an Oriq Mask from the Strixhaven sourcebook)
• Magic of mass destruction / slaughter (from the STA Day of Judgment flavor text)
• Magic made for "endless war", whatever that means (from the STA Village Rites flavor text)

It may be left ambiguous in the sourcebook so that you have the opportunity to make up evil spells, banned relics, or forbidden techniques in your game that your players encounter.

Based on some of the enemies in the sourcebooks and some of the Magic card flavor text, it seems vaguely to be:

• Blood-based magic
• Magic of mass destruction / slaughter
• Magic made for "endless war" (whatever that means)

It seems vaguely to be:

• Blood-based magic (from all the enemies with an Oriq Mask from the Strixhaven sourcebook)
• Magic of mass destruction / slaughter (from the STA Day of Judgment flavor text)
• Magic made for "endless war", whatever that means (from the STA Village Rites flavor text)

It may be left ambiguous in the sourcebook so that you have the opportunity to make up evil spells, banned relics, or forbidden techniques in your game that your players encounter.