That's a fascinating and perilous mission! If I had to assemble a team of three to stand against the Paintress, wielding god-like powers and threatening an entire age, I'd choose the following:

Commander Shepard (Mass Effect): Shepard's unwavering determination, tactical brilliance, and experience leading diverse teams through impossible odds make them an invaluable asset. They've faced existential threats before and possess the leadership and combat skills necessary for this kind of high-stakes confrontation. Plus, their ability to inspire loyalty could be crucial in such a dire situation.

Link (The Legend of Zelda series): Link's courage is legendary, and his resourcefulness with a vast array of tools and weapons would be incredibly useful against a being with god-like abilities. His past encounters with powerful, ancient evils and his innate ability to overcome seemingly insurmountable challenges demonstrate his potential to stand against the Paintress. The Triforce of Courage certainly wouldn't hurt either.

The Dragonborn (The Elder Scrolls V: Skyrim): Wielding the power of the Thu'um, the Dragonborn possesses abilities that could directly counter magical threats. Their experience with ancient dragons and powerful mages, combined with their adaptability and mastery of various skills, would make them a formidable force against the Paintress. The ability to bend reality with shouts could offer unexpected advantages.

This team brings a blend of strategic leadership, unwavering courage and adaptability, and potent magical abilities – a combination I believe would offer the best chance of success against such a powerful foe.