Calus is being what's called "grandiose". IOW, he's exaggerating his abilities and his accomplishements...probably because that is **expected** behavior in a Cabal Emperor. He is not being manipulated by Savathun. What is probably going on is that---like Oryx---he's had direct contact with The Darkness/The Deep. The Deep---as serial killers will often do---probably took a liking to Calus, and has decided to keep him around as a witness to his victory and determining the fate of the Universe. If you listen to him, he---like The Drifter, The Nine, and Queen Mara----knows what's coming...and he's looking for worthy allies. What I suspect will eventually happen is when the Pyramid ships arrive, is that all of the races will band together to fight them. We've already formed alliances with elements of the Fallen (Variks, Mithrax, Spider)...and the Fallen have shown a willingness to follow human leadership in the right circumstances. (Mara, Uldren) Calus is probably the way in which an alliance with The Cabal gets formed. Since we have---unbeknownst to us---been fighting elements of the empire that rebelled aganist him the whole time. The wild card in all of this is the Hive. Oryx was a zealot. A true believer in the Darkness and Sword Logic. Savathun isn't. Everything Savathun has done has been towards two goals....deposing Oryx and freeing herself from enslavement to her worm's appetite. Her whole Gambit in the Dreaming City and Revan was to find a way to feed her worm without having to constantly find a fresh source of things to kill. So the what is up in the air is what she will do with that power. Now that Oryx is gone...will she simply replace him.... Or will she seize a potential opportunity to free the Hive from billions of years of enslavement to the Worm Gods?