There’s an anime I’ve been looking for the past 18 years. The anime was about a young boy that stumbles upon a giant white robot that’s been dormant for some years. When the robot senses the boy, it awakens and chooses him as its pilot. To access the robot he uses some sort of scroll. During the series the giant white robot fights two guardian like robots…one is blue dog and the other is a bird or something. I’ve asked fellow anime viewers and they can’t figure it out.
In the first episode, the boy was running. He slipped and fell in the ground. Then he sees the giant white robot underground. It's attached to wires and some says it has been dormant for many years. The robot senses the boy and awakens. The boy's grandfather gave him a scroll or baton which allows him to access the robot. Along the way he battles other robots, one of them a dog and bird that are guardians who fuse together.
The boy must have been around 15 years old...he was Japanese. The robot was alien similar to a gundam. The scroll was silver with holes in it. The dog was blue and silver. The bird was yellow, looked like an ostrich. IDK why they fought but it was for good. He did leave the mecha now and again.