Having studied three of the five enemy-color gods that are due to appear in Born of the Gods and Journey into Nyx, it's time to take a look at the allied-color ones as well. First there is Ephara, the white and blue god of wisdom, and easily the most outright benevolent of the entire pantheon from what we know. Now we'll look straight across to the opposite end of that scale to a god notorious for his insane violence and senseless acts of evil - Mogis, the black and red Twin of War, brother to Iroas and god of fear and Minotaurs.
Mogis's attributes are very well-known for a minor god - he is mentioned in the names of two Theros cards and in the flavor text of two others. Mogis's Marauder is apparently a member of the gruesome Anthropophage cult of Akros, whipping his compatriots into a blind fury by use of his profane implements fashioned from still-bloody Minotaur bones. Fanatic of Mogis is a raging fire mage seen stoking an inferno in a temple of Mogis; the statue in the background confirms the fact that Mogis does indeed prefer the form of a Minotaur in the mortal realm, and he oddly enough shares a double rack of horns with Xenagos. Whether this is coincidence, a deliberate red herring to get us to assume the main villain is actually Mogis, or something far more sinister on R&D's part, it's too soon to tell.
Those flavor texts show the gruesome predilections of Mogis's followers. Borderland Minotaur's, first:
"You have led us to triumph over the forces of Mogis!" said Brygus the Brave, clapping the Champion on the back.
The Champion wiped the sweat and blood from her brow.
"I count eight graves," she said. "Too many to call this a victory."
- The Theriad
Then Deathbellow Raider's:
"The temple has been rededicated. It belongs to Mogis now." - Rastos, disciple of Mogis
Note that this "rededication" involves smashing and desecrating the building and slaughtering everyone inside.
Mechanically, Mogis is probably deadly to everyone at the table, forcing a game of attrition through mutual life loss or permanent sacrifice.
His relations with the other gods are fairly obvious: Despised by all of them for his craven, murderous ways, and his brother Iroas most of all.