This week end some of my players will be investigating in another covenant and i would really appreciate any ideas you have, here is the story so far :
Concilium Illuminati is inhabited by 4 magi :
two unspecified
Gloraïs ex Bonisagus
Oviedus ex Tytalus
Three of there sodales died in the last two years :
a Tytalus parens of one of my players who was marched for diabolism two years ago.
Relegius ex Tremere and Artesia ex Flambeau who killed each others a few months ago.
Some events :
Gloraïs lost her last apprentice in a laboratory accident
Both apprentices of Oviedus failed ther gauntlet and are used by him as lab assistant.
I suggest that you use misdirection. They will focus on the mysterious mage and diabolism. Make another mage a Jerbiton or Criamon to throw them off ( they seem harmless ).
Make it as base as gaining more vis or other resource.
An aura of 6 also warps the actual BUILDINGS and furniture, so that can be really cool: talking books that have gained sentience and recite Ovid, for example Fantasia from Disney is a nice example here
Decide how do you want the actual covenant to look like: a hamlet? a castle? a magical tower? a living tree the size of Paris?.... decide what small magics are around.
The surroundings. Magical forest inside a regio? Is it underwater in a lake? Are the inhabitants used to sleep like bats, hanging from the ceiling?
A lot of weird stuff can happen in a magical aura. Do not make it a farce, but it should be weird.
What do you want them to feel? is the place gloomy. Is it extra-bright? Do you feel a feeling of dread and there is always a pre-storm feeling around the covenant? All this kind of stuff affects the behaviour of the inhabitants and the feeling of the adventure.
The magical being under the covenant is a sleeping dragon, the magi in the covenant are trying to awaken him since many years.
He sometimes speaks in is slumber and those sentences carry the power of spells or prophecies.
His mighty power as tainted the regio, while the covenant just look like a ruined castle on the mundane level, when you enter it the top of the hill is barren and scorched as if it had been burnt.
The castle is undulating as by the heat, but it is not an illusion.
The grogs as begun to acquire some reptillian traits.
All of this point to the infernal realm but is not
The Mysterious mage has the Cthonic Magic virtue, and lots of Infernal Vis in their lab/store area that players become aware of. Strange, and suspicious, but not illegal.