For those of you that don't know/remember, 3E Red Wizards wielded immense power and were very dangerous. Players were awed every time one showed up, and they went to great lengths in fighting one on their own terms.
Red Wizards had this reputation for two main reasons. First, the Red Wizard prestige class that gave them great benefits regarding their chosen school of specialization. In short, they got huge bonuses to their spell save DCs and also to their own saving throws.
But even more alarmingly, their tattooed foreheads enabled to practice circle magic where the apprentices gave their magic power to their leader. This notable allowed the Red Wizard circle leader to add to his or her "caster level", or in 5E terms, allowed him to cast spells as if they were higher level for "free". He could also spend the circle's energies on free metamagic, which made his spells even more dangerous.
Feel free to look up the details here:
http://www.realmshelps.net/charbuild/classes/prestige/realms/red.shtml
http://www.realmshelps.net/magic/circle.shtml
Now, a direct conversion of something that already in the gonzo 3rd edition was hopelessly overpowered is not my goal.
Here are what I have come up with so far, simplifying and streamlining as much as possible while still retaining the core idea of the 3E mechanisms.
RED WIZARD TEMPLATE
Apply to any arcane spellcaster, though only Wizards (and Wizard-like monsters) gain the full benefit.
SPELL POWER: Foes save at disadvantage against spells from the Red Wizard's chosen school of specialization (if any). Example: you save with disadvantage against an Evoker Red Wizard's Fireball.
SPECIALIST DEFENSE: The Red Wizard gains magic resistance against spells of its chosen school of specialisation (if any). Example: an Evoker Red Wizard makes saves against your Fireball with advantage.
CIRCLE TATTOO: You can lead a circle of spellcasters with a circle tattoo. See below.
Circle magic: You and up to seven other spellcasters partake in a ritual that takes one hour to complete. The participant with the most levels in a single spellcasting class becomes the leader. Everyone else spends a spell slot of a spell level of their chosing (that they are normally able to cast). All these spell levels are totaled, and converted into Sorcery points on a 1:1 ratio. These sorcery points are available to the leader for 24 hours or until expended.
The circle leader can spend levels in two ways:
a) to add metamagic to his spellcasting.
b) to regain spent spell slots.
In other words, exactly as a Sorcerer would use them. Treat the circle leader as a Sorcerer with class levels equal to the circle leader's character level.
To do:
- determine exactly which metamagic effects are available
- decide whether a maximum is needed (you can't hold more sorcery points than your level)
- guesstimate how much the CR of the base monster would change because of this template