Please pay close attention my friends...

To summon the first Exogenous Demon, use this spell:

You have to read it out loud 7 times, to summon all 3 Exogenous Demons.

Each time use a different index number , like x1 = ... X2 = ....

When you've finished the 7th spell, the Exogenous Demons will appear all at once.

The Exogenous Demons may look something like this. ( but it depends on the nature of Xs you use )

Well.. now..

DO NOT let them wander around.

To summon the Endogenous ones, use this spell accordingly :

You just need to repeat it 4 times, each time giving ALL the symbols the due index (1,2,3,4)

Once you've finished the 4th spell, they will appear.

Endogenous Demons usually look something like this. ( again, it will depend on the Ys you use.)

Or if you are lucky enough, some may look like this.

Or even this, if you have enough knowledge and wisdom, or if you have spent a lot of time listening to good old Black Sabbath.

But be warned my Fellow Demon Summoners, as this type could be very deceitful. Don't fall for their siren songs or lullabies.

Now this would be the amazing moment : watch closely how they get busy with eachother, Exos with Endos. at this point they begin to interact. Watch their relations.

now...

If they made too much noise or they get out of control, you have two ways to deal with them.