This was the Sargatanas that Eligor was most accustomed to. But he had seen that other side of his lord, the fierce, turbulent personality that none in Adamantinarx, and only a relatively small number in all of Hell, could withstand. His fury could be immeasurable, and the changes it wrought on him physically were astounding. Eligor remembered sudden, organic metamorphoses that rendered his lord utterly unrecognizable. The more agitated he became, the more rapid were the shifts. Such was the fearsome power of a Demon Major. They were changes that a Demon Minor could not fully comprehend, and, to be sure, Eligor himself sometimes found them frightening.
-God’s Demon (page 60)

“They care, I am sure, enough to watch us, if for no other reason than to guard against our return. Which means that They are paying us some attention.” Sargatanas’ face was shifting. Gaps were opening and closing; tiny eyes or teeth appeared and disappeared again.
-God’s Demon (page 73)

Sargatanas strode on, outwardly oblivious to all around him. But the small bone plates of his face were ceaselessly shifting, agitated and angry.
-God's Demon (page 162)

Hani stared at his face, aquiline, broken, animated, and fierce. He saw tiny, wholly non-human bones shifting as unfathomable emotions played upon its surface. It was a face that, even in its frightful, degraded state, suggested something lost long ago—an alien grace, perhaps.
-God's Demon (page 193)

“I saw him the day he returned. His appearance was shifting so rapidly, so awfully, that were it not for his sigil I would have scarcely recognized him. The seraph has never been further from him.”
-God's Demon (page 535)