Eight days later...
If nothing else, the Master had certainly had time to observe the gathered group of Servants. There had been bickering, raging, bantering, joking, and of course rampant speculation. Plenty of information to take in about this motley crew vying for the Master's power. And yet, while the overall tenor was still that of a group that had once united to save humanity, the Master (by virtue of their vast experience) could sense a thread of malevolence somewhere in the crowd.
They'd suggested several different Servants to receive the bond with the Master, with popular opinion flitting about like a tiny airborne dog. Grail-kun had begun to despair of an actual majority opinion coalescing around any one candidate. But then! A friend who stood out among the crowd!
The Servants had come to an agreement (or enough of one for a Grail, at any rate): Assassin would bond with the Master. Not all of them had chosen Assassin, but there was a clear majority. The Master, command spells and all, finally had a Servant.
"Thank Arceus my Mystic Code means I don't need to eat and drink these days," the Master groused. "You're agreed?"
Avenger nudged Assassin forward. The Master and Assassin locked eyes for a long minute. "Let's do this," Assassin said.
The Master hesitated. "Before I take you on, I need to know something. I've sensed a force at work here that isn't on board with the spirit of friendship and such. Almost pure evil, if you will. Are you aligned with such forces?"
Assassin smiled slowly. "I am..."