From Sonic - Wiki on Neoseeker

[edit] History

Tikal the Echidna is a 14-year-old echidna. She originally makes her appearance in Sonic Adventure, where she is used as a Hint Marker, who gives advice to the player when they are in need of aid.

Originally raised by her grandmother, her tribe originated at the Mystic Ruins, and are direct ancestors to Knuckles The Echidna. Unlike the rest of her community, she is an outspoken pacifist, and strongly disagrees with her father's ideal of invading other territories. Despite her best efforts, the shrine protecting the Master Emerald is raided on orders from her father. Upon this, Chaos was unleashed upon the world. To prevent a catastrophe, Tikal sealed herself within the Master Emerald, along with Chaos.

Many years later, during the events of Sonic Adventure, Dr. Robotnik shatters the Master Emerald, and her spirit is released. Following this, she assists the main characters in stopping Robotnik and sealing Chaos once more.

[edit] Other Games

Although not directly part of the storyline, Tikal is a playable character in the Treasure Hunt multiplayer modeSonic Adventure 2.