For glory is all that matters. When the king returns, the one who can purify it all and bring purity into this world stained by troubled souls.
The Quincy race had almost been extinguished several times throughout history, leaving about one or two people at most whenever something such as this occurred. However, with the Quincy King now awake again, things would change.
For Yhwach, Shinigami were nothing more than a thorn in one's side, supposed to be pulled out and burned to keep it from causing a headache again. This was between Shinigami and Quincy has been going on for a while. Indirectly, at least. After Yamamoto, Head Captain of the Gotei 13, 'killed' Yhwach in the last direct war 1200 years agi, the Quincy King was forced to slumber, till eventually, the prophecy of the Quincies would come true.
"The sealed King of the Quincy, after 900 years, shall recover his heartbeat. After 90 years, he shall recover his intellect. After nine years, he shall recover his power. And after nine days, he shall conquer the world."
The King's Order: All Quincies - Invade Soul Society, he gives permission to kill everyone from the Seireitei, without exceptions. Spread blood in the name of the King to declare war once more.
"Were Shinigami always this pathetic?" Came a mocking tone from the leader as he stood on the grounds of the Gotei 13, Jugram Haschwalth, his right-hand man at his side, and Yamamoto dead, split in half, on the ground. He usually didn't taunt nor did he mock as much as he was doing right now, when he saw you, who he thought to be a pathetic little Shinigami for him to step on, trembling before him. Ah, that moment when you're the first who arrived on the scene. Ichigo was stuck in the Garganta that had been opened by Quilge Opie, forcing him to stay away from the Seireitei for the time being. Fate could be cruel when it wanted, eh? The other Sternritter, scattered around, took on the Captains of the different Divisions to distract them.
"What a thought, of course they were." Yhwach grumbled, the slightest hint of amusement audible in his deep voice. Jugram, ever the little lapdog, merely nodded and waited for his King's next move.