Aragog was alone. He had the local spiders, of course. But even the largest of the forest spiders were nowhere as large as he was. In fact, Aragog had outgrown the biggest local when he was two.
Because of his size, the local animals treated him as some sort of deity. "The spider god." They muttered. "The webbed one." Even the centaurs steered clear of his den. He was revered, feared, and worshiped. But he was not loved, or needed. True, the spiders lived far better lives than they had before, but they'd always enjoyed a mostly prosperous life. Aragog was superficial. Unnecessary. And alone.
"O, great one!" A small voice rang up beside him. Aragog focused on the source of the sound. It was a spider. A respectably sized one, at that. And female too. A rare combination. She came up to his first joint in height, which was no small feat. Aragog felt obliged to answer this strange, brave female.
"Who are you, little one? Why do you seek me?" Aragog boomed. Compared to the female, his voice seemed deep and threatening.
The female clicked her mandibles nervously. "They call me Mosag, o great one. I come in search for help." Mosag skittered about, agitated.
She was terrified, Aragog realized. So she should. He was the king of the forest. But her bravery was to be rewarded, and so Aragog would help. "You may call me Aragog. Now, what is it you need help with?"
"Please, Aragog, teach me how to survive! I cannot hunt as the others can, for I am too large. You are the biggest spider to ever grace the land - yet you flourish in this forest. Please teach me your secrets!" Mosag stared shakily at Aragog.
Aragog returned Mosag's stare. He sensed a certain determination, a fire in Mosag's heart. She had potential. "You have a rare gift, Mosag. Come along. I will teach you the ways of the predator."
And he did. Mosag learned. And grew. And grew some more. Soon, Mosag was nearly as large as Aragog.
And then there were two.