I only remember the first episode of the cartoon, in which a boy stole some red ruby stones from the enemy and ran. The enemies started chasing the boy. The rubies were used for activating some small animals which makes them big beast like. The boy hiding from the enemies falls in a mysterious cave. The ruby from his pocket fell out and he accidentally wakes a legendary beast from sleep, then the boy and the lion like beast fights with the enemies.
If someone remembers the show, please help.
This description sounds like the first episode of Zinba.
From MyAnimeList:
The juvenile Kan from the earth is summoned to the Kingdom of Toria , where he encounters attack from the giant creature Zinba, and he's rescued by the linker Shibuki and Uranus. Later, he accidentally gets on the linker squad DUX truck to the maze valley, finding in a cave a golden Zinba.
At around the 17:30 mark in the video below, the protagonist, Kan, hides in some bushes while a group of uniformed men wearing backpacks run by. A red jewel falls out of one of the men's backpacks, but when Kan picks it up, a large insectoid monster suddenly appears and chases him.
He ends up being cornered on a cliff by two of these monsters, and falls into a dark cave where he inadvertently awakens the title character of the show, Zinba, a huge, golden lion-beast. In his default form, Zinba is actually more like a lion cub, but when the red jewel is placed on his forehead, he transforms into his giant form.
